{"api_version":"1","generated_at":"2026-05-13T13:53:36+00:00","cve":"CVE-2024-35877","urls":{"html":"https://cve.report/CVE-2024-35877","api":"https://cve.report/api/cve/CVE-2024-35877.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2024-35877","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2024-35877"},"summary":{"title":"x86/mm/pat: fix VM_PAT handling in COW mappings","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm/pat: fix VM_PAT handling in COW mappings\n\nPAT handling won't do the right thing in COW mappings: the first PTE (or,\nin fact, all PTEs) can be replaced during write faults to point at anon\nfolios.  Reliably recovering the correct PFN and cachemode using\nfollow_phys() from PTEs will not work in COW mappings.\n\nUsing follow_phys(), we might just get the address+protection of the anon\nfolio (which is very wrong), or fail on swap/nonswap entries, failing\nfollow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and\ntrack_pfn_copy(), not properly calling free_pfn_range().\n\nIn free_pfn_range(), we either wouldn't call memtype_free() or would call\nit with the wrong range, possibly leaking memory.\n\nTo fix that, let's update follow_phys() to refuse returning anon folios,\nand fallback to using the stored PFN inside vma->vm_pgoff for COW mappings\nif we run into that.\n\nWe will now properly handle untrack_pfn() with COW mappings, where we\ndon't need the cachemode.  We'll have to fail fork()->track_pfn_copy() if\nthe first page was replaced by an anon folio, though: we'd have to store\nthe cachemode in the VMA to make this work, likely growing the VMA size.\n\nFor now, lets keep it simple and let track_pfn_copy() just fail in that\ncase: it would have failed in the past with swap/nonswap entries already,\nand it would have done the wrong thing with anon folios.\n\nSimple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():\n\n<--- C reproducer --->\n #include <stdio.h>\n #include <sys/mman.h>\n #include <unistd.h>\n #include <liburing.h>\n\n int main(void)\n {\n         struct io_uring_params p = {};\n         int ring_fd;\n         size_t size;\n         char *map;\n\n         ring_fd = io_uring_setup(1, &p);\n         if (ring_fd < 0) {\n                 perror(\"io_uring_setup\");\n                 return 1;\n         }\n         size = p.sq_off.array + p.sq_entries * sizeof(unsigned);\n\n         /* Map the submission queue ring MAP_PRIVATE */\n         map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,\n                    ring_fd, IORING_OFF_SQ_RING);\n         if (map == MAP_FAILED) {\n                 perror(\"mmap\");\n                 return 1;\n         }\n\n         /* We have at least one page. Let's COW it. */\n         *map = 0;\n         pause();\n         return 0;\n }\n<--- C reproducer --->\n\nOn a system with 16 GiB RAM and swap configured:\n # ./iouring &\n # memhog 16G\n # killall iouring\n[  301.552930] ------------[ cut here ]------------\n[  301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100\n[  301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g\n[  301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1\n[  301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4\n[  301.559569] RIP: 0010:untrack_pfn+0xf4/0x100\n[  301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000\n[  301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282\n[  301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047\n[  301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200\n[  301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000\n[  301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000\n[  301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000\n[  301.564186] FS:  0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000\n[  301.564773] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0\n[  301.565725] PKRU: 55555554\n[  301.565944] Call Trace:\n[  301.566148]  <TASK>\n[  301.566325]  ? untrack_pfn+0xf4/0x100\n[  301.566618]  ? __warn+0x81/0x130\n[  301.566876]  ? untrack_pfn+0xf4/0x100\n[  3\n---truncated---","state":"PUBLISHED","assigner":"Linux","published_at":"2024-05-19 09:15:08","updated_at":"2026-05-12 12:16:38"},"problem_types":["CWE-401","CWE-noinfo Not enough information"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html","name":"https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Third Party Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-265688.html","name":"https://cert-portal.siemens.com/productcert/html/ssa-265688.html","refsource":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/97e93367e82752e475a33839a80b33bdbef1209f","name":"https://git.kernel.org/stable/c/97e93367e82752e475a33839a80b33bdbef1209f","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6","name":"https://git.kernel.org/stable/c/1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f18681daaec9665a15c5e7e0f591aad5d0ac622b","name":"https://git.kernel.org/stable/c/f18681daaec9665a15c5e7e0f591aad5d0ac622b","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/51b7841f3fe84606ec0bd8da859d22e05e5419ec","name":"https://git.kernel.org/stable/c/51b7841f3fe84606ec0bd8da859d22e05e5419ec","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/09e6bb53217bf388a0d2fd7fb21e74ab9dffc173","name":"https://git.kernel.org/stable/c/09e6bb53217bf388a0d2fd7fb21e74ab9dffc173","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4","name":"https://git.kernel.org/stable/c/c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html","name":"https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Third Party Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7cfee26d1950250b14c5cb0a37b142f3fcc6396a","name":"https://git.kernel.org/stable/c/7cfee26d1950250b14c5cb0a37b142f3fcc6396a","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/04c35ab3bdae7fefbd7c7a7355f29fa03a035221","name":"https://git.kernel.org/stable/c/04c35ab3bdae7fefbd7c7a7355f29fa03a035221","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2024-35877","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-35877","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 f18681daaec9665a15c5e7e0f591aad5d0ac622b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 09e6bb53217bf388a0d2fd7fb21e74ab9dffc173 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 7cfee26d1950250b14c5cb0a37b142f3fcc6396a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 97e93367e82752e475a33839a80b33bdbef1209f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 51b7841f3fe84606ec0bd8da859d22e05e5419ec git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5899329b19100c0b82dc78e9b21ed8b920c9ffb3 04c35ab3bdae7fefbd7c7a7355f29fa03a035221 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.29","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.29 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.19.312 4.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.4.274 5.4.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.215 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.155 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.85 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.26 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.8.5 6.8.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.9 * original_commit_for_fix","platforms":[]},{"source":"ADP","vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","version":"affected * custom","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2024","cve_id":"35877","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"linux","cpe5":"linux_kernel","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2024-35877","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2025-01-16T21:13:41.454834Z","version":"2.0.3"},"type":"ssvc"}}],"problemTypes":[{"descriptions":[{"description":"CWE-noinfo Not enough information","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2025-01-16T21:14:37.162Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"},{"providerMetadata":{"dateUpdated":"2024-08-02T03:21:48.797Z","orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE"},"references":[{"tags":["x_transferred"],"url":"https://git.kernel.org/stable/c/f18681daaec9665a15c5e7e0f591aad5d0ac622b"},{"tags":["x_transferred"],"url":"https://git.kernel.org/stable/c/09e6bb53217bf388a0d2fd7fb21e74ab9dffc173"},{"tags":["x_transferred"],"url":"https://git.kernel.org/stable/c/c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4"},{"tags":["x_transferred"],"url":"https://git.kernel.org/stable/c/7cfee26d1950250b14c5cb0a37b142f3fcc6396a"},{"tags":["x_transferred"],"url":"https://git.kernel.org/stable/c/97e93367e82752e475a33839a80b33bdbef1209f"},{"tags":["x_transferred"],"url":"https://git.kernel.org/stable/c/51b7841f3fe84606ec0bd8da859d22e05e5419ec"},{"tags":["x_transferred"],"url":"https://git.kernel.org/stable/c/1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6"},{"tags":["x_transferred"],"url":"https://git.kernel.org/stable/c/04c35ab3bdae7fefbd7c7a7355f29fa03a035221"},{"tags":["x_transferred"],"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html"},{"tags":["x_transferred"],"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html"}],"title":"CVE Program Container"},{"affected":[{"defaultStatus":"unknown","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","vendor":"Siemens","versions":[{"lessThan":"*","status":"affected","version":"0","versionType":"custom"}]}],"providerMetadata":{"dateUpdated":"2026-05-12T11:52:17.843Z","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","shortName":"siemens-SADP"},"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-265688.html"}],"x_adpType":"supplier"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["arch/x86/mm/pat/memtype.c","mm/memory.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"f18681daaec9665a15c5e7e0f591aad5d0ac622b","status":"affected","version":"5899329b19100c0b82dc78e9b21ed8b920c9ffb3","versionType":"git"},{"lessThan":"09e6bb53217bf388a0d2fd7fb21e74ab9dffc173","status":"affected","version":"5899329b19100c0b82dc78e9b21ed8b920c9ffb3","versionType":"git"},{"lessThan":"c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4","status":"affected","version":"5899329b19100c0b82dc78e9b21ed8b920c9ffb3","versionType":"git"},{"lessThan":"7cfee26d1950250b14c5cb0a37b142f3fcc6396a","status":"affected","version":"5899329b19100c0b82dc78e9b21ed8b920c9ffb3","versionType":"git"},{"lessThan":"97e93367e82752e475a33839a80b33bdbef1209f","status":"affected","version":"5899329b19100c0b82dc78e9b21ed8b920c9ffb3","versionType":"git"},{"lessThan":"51b7841f3fe84606ec0bd8da859d22e05e5419ec","status":"affected","version":"5899329b19100c0b82dc78e9b21ed8b920c9ffb3","versionType":"git"},{"lessThan":"1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6","status":"affected","version":"5899329b19100c0b82dc78e9b21ed8b920c9ffb3","versionType":"git"},{"lessThan":"04c35ab3bdae7fefbd7c7a7355f29fa03a035221","status":"affected","version":"5899329b19100c0b82dc78e9b21ed8b920c9ffb3","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["arch/x86/mm/pat/memtype.c","mm/memory.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.29"},{"lessThan":"2.6.29","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"4.19.*","status":"unaffected","version":"4.19.312","versionType":"semver"},{"lessThanOrEqual":"5.4.*","status":"unaffected","version":"5.4.274","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.215","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.155","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.85","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.26","versionType":"semver"},{"lessThanOrEqual":"6.8.*","status":"unaffected","version":"6.8.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.9","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"4.19.312","versionStartIncluding":"2.6.29","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.4.274","versionStartIncluding":"2.6.29","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.215","versionStartIncluding":"2.6.29","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.155","versionStartIncluding":"2.6.29","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.85","versionStartIncluding":"2.6.29","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.26","versionStartIncluding":"2.6.29","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.8.5","versionStartIncluding":"2.6.29","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.9","versionStartIncluding":"2.6.29","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm/pat: fix VM_PAT handling in COW mappings\n\nPAT handling won't do the right thing in COW mappings: the first PTE (or,\nin fact, all PTEs) can be replaced during write faults to point at anon\nfolios.  Reliably recovering the correct PFN and cachemode using\nfollow_phys() from PTEs will not work in COW mappings.\n\nUsing follow_phys(), we might just get the address+protection of the anon\nfolio (which is very wrong), or fail on swap/nonswap entries, failing\nfollow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and\ntrack_pfn_copy(), not properly calling free_pfn_range().\n\nIn free_pfn_range(), we either wouldn't call memtype_free() or would call\nit with the wrong range, possibly leaking memory.\n\nTo fix that, let's update follow_phys() to refuse returning anon folios,\nand fallback to using the stored PFN inside vma->vm_pgoff for COW mappings\nif we run into that.\n\nWe will now properly handle untrack_pfn() with COW mappings, where we\ndon't need the cachemode.  We'll have to fail fork()->track_pfn_copy() if\nthe first page was replaced by an anon folio, though: we'd have to store\nthe cachemode in the VMA to make this work, likely growing the VMA size.\n\nFor now, lets keep it simple and let track_pfn_copy() just fail in that\ncase: it would have failed in the past with swap/nonswap entries already,\nand it would have done the wrong thing with anon folios.\n\nSimple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():\n\n<--- C reproducer --->\n #include <stdio.h>\n #include <sys/mman.h>\n #include <unistd.h>\n #include <liburing.h>\n\n int main(void)\n {\n         struct io_uring_params p = {};\n         int ring_fd;\n         size_t size;\n         char *map;\n\n         ring_fd = io_uring_setup(1, &p);\n         if (ring_fd < 0) {\n                 perror(\"io_uring_setup\");\n                 return 1;\n         }\n         size = p.sq_off.array + p.sq_entries * sizeof(unsigned);\n\n         /* Map the submission queue ring MAP_PRIVATE */\n         map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,\n                    ring_fd, IORING_OFF_SQ_RING);\n         if (map == MAP_FAILED) {\n                 perror(\"mmap\");\n                 return 1;\n         }\n\n         /* We have at least one page. Let's COW it. */\n         *map = 0;\n         pause();\n         return 0;\n }\n<--- C reproducer --->\n\nOn a system with 16 GiB RAM and swap configured:\n # ./iouring &\n # memhog 16G\n # killall iouring\n[  301.552930] ------------[ cut here ]------------\n[  301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100\n[  301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g\n[  301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1\n[  301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4\n[  301.559569] RIP: 0010:untrack_pfn+0xf4/0x100\n[  301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000\n[  301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282\n[  301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047\n[  301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200\n[  301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000\n[  301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000\n[  301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000\n[  301.564186] FS:  0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000\n[  301.564773] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0\n[  301.565725] PKRU: 55555554\n[  301.565944] Call Trace:\n[  301.566148]  <TASK>\n[  301.566325]  ? untrack_pfn+0xf4/0x100\n[  301.566618]  ? __warn+0x81/0x130\n[  301.566876]  ? untrack_pfn+0xf4/0x100\n[  3\n---truncated---"}],"providerMetadata":{"dateUpdated":"2026-05-11T20:12:58.539Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/f18681daaec9665a15c5e7e0f591aad5d0ac622b"},{"url":"https://git.kernel.org/stable/c/09e6bb53217bf388a0d2fd7fb21e74ab9dffc173"},{"url":"https://git.kernel.org/stable/c/c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4"},{"url":"https://git.kernel.org/stable/c/7cfee26d1950250b14c5cb0a37b142f3fcc6396a"},{"url":"https://git.kernel.org/stable/c/97e93367e82752e475a33839a80b33bdbef1209f"},{"url":"https://git.kernel.org/stable/c/51b7841f3fe84606ec0bd8da859d22e05e5419ec"},{"url":"https://git.kernel.org/stable/c/1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6"},{"url":"https://git.kernel.org/stable/c/04c35ab3bdae7fefbd7c7a7355f29fa03a035221"}],"title":"x86/mm/pat: fix VM_PAT handling in COW mappings","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2024-35877","datePublished":"2024-05-19T08:34:34.604Z","dateReserved":"2024-05-17T13:50:33.110Z","dateUpdated":"2026-05-12T11:52:17.843Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2024-05-19 09:15:08","lastModifiedDate":"2026-05-12 12:16:38","problem_types":["CWE-401","CWE-noinfo Not enough information"],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"4.19.312","matchCriteriaId":"FC6D429D-BBC0-45CE-BDD8-A62B2EF8F67A"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"5.4.274","matchCriteriaId":"F45A0F3C-C16D-49C4-86D6-D021C3D4B834"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"5.10.215","matchCriteriaId":"9CD5894E-58E9-4B4A-B0F4-3E6BC134B8F5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.15.155","matchCriteriaId":"F11B6314-A852-4FBD-AD84-ECE23F5C092B"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.1.85","matchCriteriaId":"325665BF-2409-49D9-B391-39AD4566FDBD"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.26","matchCriteriaId":"C520696A-A594-4FFC-A32D-12DA535CE911"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.8.5","matchCriteriaId":"DBD6C99E-4250-4DFE-8447-FF2075939D10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:*","matchCriteriaId":"22BEDD49-2C6D-402D-9DBF-6646F6ECD10B"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.9:rc2:*:*:*:*:*:*","matchCriteriaId":"DF73CB2A-DFFD-46FB-9BFE-AA394F27EA37"}]}]},{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*","matchCriteriaId":"07B237A9-69A3-4A9C-9DA0-4E06BD37AE73"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2024","CveId":"35877","Ordinal":"1","Title":"x86/mm/pat: fix VM_PAT handling in COW mappings","CVE":"CVE-2024-35877","Year":"2024"},"notes":[{"CveYear":"2024","CveId":"35877","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm/pat: fix VM_PAT handling in COW mappings\n\nPAT handling won't do the right thing in COW mappings: the first PTE (or,\nin fact, all PTEs) can be replaced during write faults to point at anon\nfolios.  Reliably recovering the correct PFN and cachemode using\nfollow_phys() from PTEs will not work in COW mappings.\n\nUsing follow_phys(), we might just get the address+protection of the anon\nfolio (which is very wrong), or fail on swap/nonswap entries, failing\nfollow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and\ntrack_pfn_copy(), not properly calling free_pfn_range().\n\nIn free_pfn_range(), we either wouldn't call memtype_free() or would call\nit with the wrong range, possibly leaking memory.\n\nTo fix that, let's update follow_phys() to refuse returning anon folios,\nand fallback to using the stored PFN inside vma->vm_pgoff for COW mappings\nif we run into that.\n\nWe will now properly handle untrack_pfn() with COW mappings, where we\ndon't need the cachemode.  We'll have to fail fork()->track_pfn_copy() if\nthe first page was replaced by an anon folio, though: we'd have to store\nthe cachemode in the VMA to make this work, likely growing the VMA size.\n\nFor now, lets keep it simple and let track_pfn_copy() just fail in that\ncase: it would have failed in the past with swap/nonswap entries already,\nand it would have done the wrong thing with anon folios.\n\nSimple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():\n\n<--- C reproducer --->\n #include <stdio.h>\n #include <sys/mman.h>\n #include <unistd.h>\n #include <liburing.h>\n\n int main(void)\n {\n         struct io_uring_params p = {};\n         int ring_fd;\n         size_t size;\n         char *map;\n\n         ring_fd = io_uring_setup(1, &p);\n         if (ring_fd < 0) {\n                 perror(\"io_uring_setup\");\n                 return 1;\n         }\n         size = p.sq_off.array + p.sq_entries * sizeof(unsigned);\n\n         /* Map the submission queue ring MAP_PRIVATE */\n         map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,\n                    ring_fd, IORING_OFF_SQ_RING);\n         if (map == MAP_FAILED) {\n                 perror(\"mmap\");\n                 return 1;\n         }\n\n         /* We have at least one page. Let's COW it. */\n         *map = 0;\n         pause();\n         return 0;\n }\n<--- C reproducer --->\n\nOn a system with 16 GiB RAM and swap configured:\n # ./iouring &\n # memhog 16G\n # killall iouring\n[  301.552930] ------------[ cut here ]------------\n[  301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100\n[  301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g\n[  301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1\n[  301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4\n[  301.559569] RIP: 0010:untrack_pfn+0xf4/0x100\n[  301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000\n[  301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282\n[  301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047\n[  301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200\n[  301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000\n[  301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000\n[  301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000\n[  301.564186] FS:  0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000\n[  301.564773] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0\n[  301.565725] PKRU: 55555554\n[  301.565944] Call Trace:\n[  301.566148]  <TASK>\n[  301.566325]  ? untrack_pfn+0xf4/0x100\n[  301.566618]  ? __warn+0x81/0x130\n[  301.566876]  ? untrack_pfn+0xf4/0x100\n[  3\n---truncated---","Type":"Description","Title":"x86/mm/pat: fix VM_PAT handling in COW mappings"}]}}}