{"api_version":"1","generated_at":"2026-09-12T02:59:37+00:00","cve":"CVE-2026-89754","urls":{"html":"https://cve.report/CVE-2026-89754","api":"https://cve.report/api/cve/CVE-2026-89754.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-89754","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-89754"},"summary":{"title":"mm/pagewalk: fix stale walk->action escaping walk_pmd_range()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/pagewalk: fix stale walk->action escaping walk_pmd_range()\n\nIf ->pmd_entry() sets walk->action = ACTION_AGAIN, the pmd_none() check is\nretried.  The PMD entry may be cleared at the point of retry.\n\nIn this case, if walk->ops->install_pte is not specified, the code\ncontinues to the next PMD entry in the range without resetting\nwalk->action to ACTION_SUBTREE.\n\nThis leaves walk->action erroneously set to ACTION_AGAIN, which is\nincorrect.\n\nThis was incorrect but not problematic up until commit 3b89863c3fa4\n(\"mm/pagewalk: fix race between concurrent split and refault\") which\nupdated walk_pud_range() to check for walk->action == ACTION_AGAIN upon\nwalk_pmd_range()'s return, causing the PUD walk to be retried.\n\nIn this case this results in duplicate walk callbacks being invoked,\nwhich is erroneous and will break any caller that is not idempotent\nwith respect to this (and waste time for those which are).  The result\nis an out-of-bounds write, triggered by a local fuzzer:\n\n[    2.272695] ==================================================================\n[    2.273471] BUG: KASAN: slab-out-of-bounds in __mincore_unmapped_range+0x14f/0x190\n[    2.274302] Write of size 1 at addr ffff888008d9b000 by task poc/106\n[    2.274966]\n[    2.275154] CPU: 0 UID: 1000 PID: 106 Comm: poc Not tainted 7.2.0-rc6-00429-ga7c7074b58d2 #55 PREEMPT(lazy)\n[    2.275159] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[    2.275164] Call Trace:\n[    2.275170]  <TASK>\n[    2.275172]  dump_stack_lvl+0x53/0x70\n[    2.275200]  print_report+0xd0/0x630\n[    2.275210]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n[    2.275219]  ? irqentry_exit+0xd2/0x670\n[    2.275224]  ? irqentry_exit+0xd2/0x670\n[    2.275226]  ? __virt_addr_valid+0xef/0x1a0\n[    2.275239]  ? __mincore_unmapped_range+0x14f/0x190\n[    2.275242]  kasan_report+0xce/0x100\n[    2.275245]  ? __mincore_unmapped_range+0x14f/0x190\n[    2.275248]  __mincore_unmapped_range+0x14f/0x190\n[    2.275252]  mincore_unmapped_range+0x45/0x70\n[    2.275254]  walk_pgd_range+0xafc/0xfc0\n[    2.275261]  ? __pfx_walk_pgd_range+0x10/0x10\n[    2.275264]  ? __update_load_avg_se+0x3d1/0x670\n[    2.275275]  __walk_page_range+0xc0/0x310\n[    2.275278]  ? __pfx_find_vma+0x10/0x10\n[    2.275281]  ? finish_task_switch.isra.0+0x16d/0x4f0\n[    2.275290]  walk_page_range_mm_unsafe+0x26f/0x3a0\n[    2.275293]  ? __pfx_mtree_load+0x10/0x10\n[    2.275298]  ? __pfx_walk_page_range_mm_unsafe+0x10/0x10\n[    2.275302]  ? __free_frozen_pages+0x54d/0x7e0\n[    2.275308]  __do_sys_mincore+0x132/0x380\n[    2.275311]  do_syscall_64+0xf9/0x540\n[    2.275316]  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[    2.275322] RIP: 0033:0x422ccd\n[    2.275326] Code: b3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48\n[    2.275329] RSP: 002b:00007fffffffec18 EFLAGS: 00000287 ORIG_RAX: 000000000000001b\n[    2.275337] RAX: ffffffffffffffda RBX: 0000000000000066 RCX: 0000000000422ccd\n[    2.275339] RDX: 00000000004d0940 RSI: 0000000001000000 RDI: 00007ffff4000000\n[    2.275340] RBP: 00000000004d0940 R08: 0000000000000100 R09: 0000000000000100\n[    2.275342] R10: 0000000000000100 R11: 0000000000000287 R12: 20c49ba5e353f7cf\n[    2.275343] R13: 00000000004990d3 R14: 0000000000000000 R15: 0000000000000001\n[    2.275346]  </TASK>\n[    2.275347]\n[    2.296904] The buggy address belongs to the object at ffff888008d9b000\n[    2.296904]  which belongs to the cache sigqueue of size 80\n[    2.298151] The buggy address is located 0 bytes inside of\n[    2.298151]  allocated 80-byte region [ffff888008d9b000, ffff888008d9b050)\n[    2.299408]\n[    2.299601] The buggy address belongs to the physical page:\n[    2.300191] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8d9b\n---truncated---","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-11 20:20:06","updated_at":"2026-09-11 20:20:06"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/895cd4ecbb2e03d7583103c65ee5adaae126ed6d","name":"https://git.kernel.org/stable/c/895cd4ecbb2e03d7583103c65ee5adaae126ed6d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/aedf2efd18977e0cef7eb963166e2b1fcc0aa321","name":"https://git.kernel.org/stable/c/aedf2efd18977e0cef7eb963166e2b1fcc0aa321","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c05cdc2ab365b98099386e6c166b9865a4f2a9d3","name":"https://git.kernel.org/stable/c/c05cdc2ab365b98099386e6c166b9865a4f2a9d3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89754","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89754","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 38ec58670a0c5fc1edabdeccd857e586b7b3f318 895cd4ecbb2e03d7583103c65ee5adaae126ed6d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3b89863c3fa482912911cd65a12a3aeef662c250 c05cdc2ab365b98099386e6c166b9865a4f2a9d3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3b89863c3fa482912911cd65a12a3aeef662c250 aedf2efd18977e0cef7eb963166e2b1fcc0aa321 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9bbbebd94dd5be25ec8c899d46ef01b33d5d22c0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18.21 6.18.50 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.19.11 6.20 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.0","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.50 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.4 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["mm/pagewalk.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"895cd4ecbb2e03d7583103c65ee5adaae126ed6d","status":"affected","version":"38ec58670a0c5fc1edabdeccd857e586b7b3f318","versionType":"git"},{"lessThan":"c05cdc2ab365b98099386e6c166b9865a4f2a9d3","status":"affected","version":"3b89863c3fa482912911cd65a12a3aeef662c250","versionType":"git"},{"lessThan":"aedf2efd18977e0cef7eb963166e2b1fcc0aa321","status":"affected","version":"3b89863c3fa482912911cd65a12a3aeef662c250","versionType":"git"},{"status":"affected","version":"9bbbebd94dd5be25ec8c899d46ef01b33d5d22c0","versionType":"git"},{"lessThan":"6.18.50","status":"affected","version":"6.18.21","versionType":"semver"},{"lessThan":"6.20","status":"affected","version":"6.19.11","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["mm/pagewalk.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"7.0"},{"lessThan":"7.0","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.50","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.50","versionStartIncluding":"6.18.21","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.4","versionStartIncluding":"7.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc1","versionStartIncluding":"7.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19.11","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/pagewalk: fix stale walk->action escaping walk_pmd_range()\n\nIf ->pmd_entry() sets walk->action = ACTION_AGAIN, the pmd_none() check is\nretried.  The PMD entry may be cleared at the point of retry.\n\nIn this case, if walk->ops->install_pte is not specified, the code\ncontinues to the next PMD entry in the range without resetting\nwalk->action to ACTION_SUBTREE.\n\nThis leaves walk->action erroneously set to ACTION_AGAIN, which is\nincorrect.\n\nThis was incorrect but not problematic up until commit 3b89863c3fa4\n(\"mm/pagewalk: fix race between concurrent split and refault\") which\nupdated walk_pud_range() to check for walk->action == ACTION_AGAIN upon\nwalk_pmd_range()'s return, causing the PUD walk to be retried.\n\nIn this case this results in duplicate walk callbacks being invoked,\nwhich is erroneous and will break any caller that is not idempotent\nwith respect to this (and waste time for those which are).  The result\nis an out-of-bounds write, triggered by a local fuzzer:\n\n[    2.272695] ==================================================================\n[    2.273471] BUG: KASAN: slab-out-of-bounds in __mincore_unmapped_range+0x14f/0x190\n[    2.274302] Write of size 1 at addr ffff888008d9b000 by task poc/106\n[    2.274966]\n[    2.275154] CPU: 0 UID: 1000 PID: 106 Comm: poc Not tainted 7.2.0-rc6-00429-ga7c7074b58d2 #55 PREEMPT(lazy)\n[    2.275159] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[    2.275164] Call Trace:\n[    2.275170]  <TASK>\n[    2.275172]  dump_stack_lvl+0x53/0x70\n[    2.275200]  print_report+0xd0/0x630\n[    2.275210]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n[    2.275219]  ? irqentry_exit+0xd2/0x670\n[    2.275224]  ? irqentry_exit+0xd2/0x670\n[    2.275226]  ? __virt_addr_valid+0xef/0x1a0\n[    2.275239]  ? __mincore_unmapped_range+0x14f/0x190\n[    2.275242]  kasan_report+0xce/0x100\n[    2.275245]  ? __mincore_unmapped_range+0x14f/0x190\n[    2.275248]  __mincore_unmapped_range+0x14f/0x190\n[    2.275252]  mincore_unmapped_range+0x45/0x70\n[    2.275254]  walk_pgd_range+0xafc/0xfc0\n[    2.275261]  ? __pfx_walk_pgd_range+0x10/0x10\n[    2.275264]  ? __update_load_avg_se+0x3d1/0x670\n[    2.275275]  __walk_page_range+0xc0/0x310\n[    2.275278]  ? __pfx_find_vma+0x10/0x10\n[    2.275281]  ? finish_task_switch.isra.0+0x16d/0x4f0\n[    2.275290]  walk_page_range_mm_unsafe+0x26f/0x3a0\n[    2.275293]  ? __pfx_mtree_load+0x10/0x10\n[    2.275298]  ? __pfx_walk_page_range_mm_unsafe+0x10/0x10\n[    2.275302]  ? __free_frozen_pages+0x54d/0x7e0\n[    2.275308]  __do_sys_mincore+0x132/0x380\n[    2.275311]  do_syscall_64+0xf9/0x540\n[    2.275316]  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[    2.275322] RIP: 0033:0x422ccd\n[    2.275326] Code: b3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48\n[    2.275329] RSP: 002b:00007fffffffec18 EFLAGS: 00000287 ORIG_RAX: 000000000000001b\n[    2.275337] RAX: ffffffffffffffda RBX: 0000000000000066 RCX: 0000000000422ccd\n[    2.275339] RDX: 00000000004d0940 RSI: 0000000001000000 RDI: 00007ffff4000000\n[    2.275340] RBP: 00000000004d0940 R08: 0000000000000100 R09: 0000000000000100\n[    2.275342] R10: 0000000000000100 R11: 0000000000000287 R12: 20c49ba5e353f7cf\n[    2.275343] R13: 00000000004990d3 R14: 0000000000000000 R15: 0000000000000001\n[    2.275346]  </TASK>\n[    2.275347]\n[    2.296904] The buggy address belongs to the object at ffff888008d9b000\n[    2.296904]  which belongs to the cache sigqueue of size 80\n[    2.298151] The buggy address is located 0 bytes inside of\n[    2.298151]  allocated 80-byte region [ffff888008d9b000, ffff888008d9b050)\n[    2.299408]\n[    2.299601] The buggy address belongs to the physical page:\n[    2.300191] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8d9b\n---truncated---"}],"providerMetadata":{"dateUpdated":"2026-09-11T19:46:57.534Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/895cd4ecbb2e03d7583103c65ee5adaae126ed6d"},{"url":"https://git.kernel.org/stable/c/c05cdc2ab365b98099386e6c166b9865a4f2a9d3"},{"url":"https://git.kernel.org/stable/c/aedf2efd18977e0cef7eb963166e2b1fcc0aa321"}],"title":"mm/pagewalk: fix stale walk->action escaping walk_pmd_range()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-89754","datePublished":"2026-09-11T19:46:57.534Z","dateReserved":"2026-09-11T19:38:34.763Z","dateUpdated":"2026-09-11T19:46:57.534Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-11 20:20:06","lastModifiedDate":"2026-09-11 20:20:06","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"89754","Ordinal":"1","Title":"mm/pagewalk: fix stale walk->action escaping walk_pmd_range()","CVE":"CVE-2026-89754","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"89754","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/pagewalk: fix stale walk->action escaping walk_pmd_range()\n\nIf ->pmd_entry() sets walk->action = ACTION_AGAIN, the pmd_none() check is\nretried.  The PMD entry may be cleared at the point of retry.\n\nIn this case, if walk->ops->install_pte is not specified, the code\ncontinues to the next PMD entry in the range without resetting\nwalk->action to ACTION_SUBTREE.\n\nThis leaves walk->action erroneously set to ACTION_AGAIN, which is\nincorrect.\n\nThis was incorrect but not problematic up until commit 3b89863c3fa4\n(\"mm/pagewalk: fix race between concurrent split and refault\") which\nupdated walk_pud_range() to check for walk->action == ACTION_AGAIN upon\nwalk_pmd_range()'s return, causing the PUD walk to be retried.\n\nIn this case this results in duplicate walk callbacks being invoked,\nwhich is erroneous and will break any caller that is not idempotent\nwith respect to this (and waste time for those which are).  The result\nis an out-of-bounds write, triggered by a local fuzzer:\n\n[    2.272695] ==================================================================\n[    2.273471] BUG: KASAN: slab-out-of-bounds in __mincore_unmapped_range+0x14f/0x190\n[    2.274302] Write of size 1 at addr ffff888008d9b000 by task poc/106\n[    2.274966]\n[    2.275154] CPU: 0 UID: 1000 PID: 106 Comm: poc Not tainted 7.2.0-rc6-00429-ga7c7074b58d2 #55 PREEMPT(lazy)\n[    2.275159] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[    2.275164] Call Trace:\n[    2.275170]  <TASK>\n[    2.275172]  dump_stack_lvl+0x53/0x70\n[    2.275200]  print_report+0xd0/0x630\n[    2.275210]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n[    2.275219]  ? irqentry_exit+0xd2/0x670\n[    2.275224]  ? irqentry_exit+0xd2/0x670\n[    2.275226]  ? __virt_addr_valid+0xef/0x1a0\n[    2.275239]  ? __mincore_unmapped_range+0x14f/0x190\n[    2.275242]  kasan_report+0xce/0x100\n[    2.275245]  ? __mincore_unmapped_range+0x14f/0x190\n[    2.275248]  __mincore_unmapped_range+0x14f/0x190\n[    2.275252]  mincore_unmapped_range+0x45/0x70\n[    2.275254]  walk_pgd_range+0xafc/0xfc0\n[    2.275261]  ? __pfx_walk_pgd_range+0x10/0x10\n[    2.275264]  ? __update_load_avg_se+0x3d1/0x670\n[    2.275275]  __walk_page_range+0xc0/0x310\n[    2.275278]  ? __pfx_find_vma+0x10/0x10\n[    2.275281]  ? finish_task_switch.isra.0+0x16d/0x4f0\n[    2.275290]  walk_page_range_mm_unsafe+0x26f/0x3a0\n[    2.275293]  ? __pfx_mtree_load+0x10/0x10\n[    2.275298]  ? __pfx_walk_page_range_mm_unsafe+0x10/0x10\n[    2.275302]  ? __free_frozen_pages+0x54d/0x7e0\n[    2.275308]  __do_sys_mincore+0x132/0x380\n[    2.275311]  do_syscall_64+0xf9/0x540\n[    2.275316]  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[    2.275322] RIP: 0033:0x422ccd\n[    2.275326] Code: b3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48\n[    2.275329] RSP: 002b:00007fffffffec18 EFLAGS: 00000287 ORIG_RAX: 000000000000001b\n[    2.275337] RAX: ffffffffffffffda RBX: 0000000000000066 RCX: 0000000000422ccd\n[    2.275339] RDX: 00000000004d0940 RSI: 0000000001000000 RDI: 00007ffff4000000\n[    2.275340] RBP: 00000000004d0940 R08: 0000000000000100 R09: 0000000000000100\n[    2.275342] R10: 0000000000000100 R11: 0000000000000287 R12: 20c49ba5e353f7cf\n[    2.275343] R13: 00000000004990d3 R14: 0000000000000000 R15: 0000000000000001\n[    2.275346]  </TASK>\n[    2.275347]\n[    2.296904] The buggy address belongs to the object at ffff888008d9b000\n[    2.296904]  which belongs to the cache sigqueue of size 80\n[    2.298151] The buggy address is located 0 bytes inside of\n[    2.298151]  allocated 80-byte region [ffff888008d9b000, ffff888008d9b050)\n[    2.299408]\n[    2.299601] The buggy address belongs to the physical page:\n[    2.300191] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8d9b\n---truncated---","Type":"Description","Title":"mm/pagewalk: fix stale walk->action escaping walk_pmd_range()"}]}}}