{"api_version":"1","generated_at":"2026-09-11T18:21:36+00:00","cve":"CVE-2024-44946","urls":{"html":"https://cve.report/CVE-2024-44946","api":"https://cve.report/api/cve/CVE-2024-44946.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2024-44946","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2024-44946"},"summary":{"title":"kcm: Serialise kcm_sendmsg() for the same socket.","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nkcm: Serialise kcm_sendmsg() for the same socket.\n\nsyzkaller reported UAF in kcm_release(). [0]\n\nThe scenario is\n\n  1. Thread A builds a skb with MSG_MORE and sets kcm->seq_skb.\n\n  2. Thread A resumes building skb from kcm->seq_skb but is blocked\n     by sk_stream_wait_memory()\n\n  3. Thread B calls sendmsg() concurrently, finishes building kcm->seq_skb\n     and puts the skb to the write queue\n\n  4. Thread A faces an error and finally frees skb that is already in the\n     write queue\n\n  5. kcm_release() does double-free the skb in the write queue\n\nWhen a thread is building a MSG_MORE skb, another thread must not touch it.\n\nLet's add a per-sk mutex and serialise kcm_sendmsg().\n\n[0]:\nBUG: KASAN: slab-use-after-free in __skb_unlink include/linux/skbuff.h:2366 [inline]\nBUG: KASAN: slab-use-after-free in __skb_dequeue include/linux/skbuff.h:2385 [inline]\nBUG: KASAN: slab-use-after-free in __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]\nBUG: KASAN: slab-use-after-free in __skb_queue_purge include/linux/skbuff.h:3181 [inline]\nBUG: KASAN: slab-use-after-free in kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691\nRead of size 8 at addr ffff0000ced0fc80 by task syz-executor329/6167\n\nCPU: 1 PID: 6167 Comm: syz-executor329 Tainted: G    B              6.8.0-rc5-syzkaller-g9abbc24128bc #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024\nCall trace:\n dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291\n show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x178/0x518 mm/kasan/report.c:488\n kasan_report+0xd8/0x138 mm/kasan/report.c:601\n __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381\n __skb_unlink include/linux/skbuff.h:2366 [inline]\n __skb_dequeue include/linux/skbuff.h:2385 [inline]\n __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]\n __skb_queue_purge include/linux/skbuff.h:3181 [inline]\n kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691\n __sock_release net/socket.c:659 [inline]\n sock_close+0xa4/0x1e8 net/socket.c:1421\n __fput+0x30c/0x738 fs/file_table.c:376\n ____fput+0x20/0x30 fs/file_table.c:404\n task_work_run+0x230/0x2e0 kernel/task_work.c:180\n exit_task_work include/linux/task_work.h:38 [inline]\n do_exit+0x618/0x1f64 kernel/exit.c:871\n do_group_exit+0x194/0x22c kernel/exit.c:1020\n get_signal+0x1500/0x15ec kernel/signal.c:2893\n do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249\n do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148\n exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]\n exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]\n el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713\n el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730\n el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598\n\nAllocated by task 6166:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x40/0x78 mm/kasan/common.c:68\n kasan_save_alloc_info+0x70/0x84 mm/kasan/generic.c:626\n unpoison_slab_object mm/kasan/common.c:314 [inline]\n __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:340\n kasan_slab_alloc include/linux/kasan.h:201 [inline]\n slab_post_alloc_hook mm/slub.c:3813 [inline]\n slab_alloc_node mm/slub.c:3860 [inline]\n kmem_cache_alloc_node+0x204/0x4c0 mm/slub.c:3903\n __alloc_skb+0x19c/0x3d8 net/core/skbuff.c:641\n alloc_skb include/linux/skbuff.h:1296 [inline]\n kcm_sendmsg+0x1d3c/0x2124 net/kcm/kcmsock.c:783\n sock_sendmsg_nosec net/socket.c:730 [inline]\n __sock_sendmsg net/socket.c:745 [inline]\n sock_sendmsg+0x220/0x2c0 net/socket.c:768\n splice_to_socket+0x7cc/0xd58 fs/splice.c:889\n do_splice_from fs/splice.c:941 [inline]\n direct_splice_actor+0xec/0x1d8 fs/splice.c:1164\n splice_direct_to_actor+0x438/0xa0c fs/splice.c:1108\n do_splice_direct_actor \n---truncated---","state":"PUBLISHED","assigner":"Linux","published_at":"2024-08-31 14:15:04","updated_at":"2026-08-04 11:20:02"},"problem_types":["CWE-416"],"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"}},{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/9c8d544ed619f704e2b70e63e08ab75630c2ea23","name":"https://git.kernel.org/stable/c/9c8d544ed619f704e2b70e63e08ab75630c2ea23","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fa6c23fe6dcac8c8bd63920ee8681292a2bd544e","name":"https://git.kernel.org/stable/c/fa6c23fe6dcac8c8bd63920ee8681292a2bd544e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/807067bf014d4a3ae2cc55bd3de16f22a01eb580","name":"https://git.kernel.org/stable/c/807067bf014d4a3ae2cc55bd3de16f22a01eb580","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/eb06c8d3022ce6738711191c89f9b3e9cfb91914","name":"https://git.kernel.org/stable/c/eb06c8d3022ce6738711191c89f9b3e9cfb91914","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8c9cdbf600143bd6835c8b8351e5ac956da79aec","name":"https://git.kernel.org/stable/c/8c9cdbf600143bd6835c8b8351e5ac956da79aec","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html","name":"https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6633b17840bf828921254d788ccd15602843fe9b","name":"https://git.kernel.org/stable/c/6633b17840bf828921254d788ccd15602843fe9b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/00425508f30baa5ab6449a1f478480ca7cffa6da","name":"https://git.kernel.org/stable/c/00425508f30baa5ab6449a1f478480ca7cffa6da","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html","name":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html","refsource":"af854a3a-2127-422b-91ae-364da2661108","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/72da240aafb142630cf16adc803ccdacb3780849","name":"https://git.kernel.org/stable/c/72da240aafb142630cf16adc803ccdacb3780849","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2024-44946","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-44946","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 8c9cdbf600143bd6835c8b8351e5ac956da79aec git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 6633b17840bf828921254d788ccd15602843fe9b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 eb06c8d3022ce6738711191c89f9b3e9cfb91914 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 fa6c23fe6dcac8c8bd63920ee8681292a2bd544e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 72da240aafb142630cf16adc803ccdacb3780849 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 00425508f30baa5ab6449a1f478480ca7cffa6da git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 9c8d544ed619f704e2b70e63e08ab75630c2ea23 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 807067bf014d4a3ae2cc55bd3de16f22a01eb580 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.6","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.6 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.19.321 4.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.4.283 5.4.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.225 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.166 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.107 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.48 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.10.7 6.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.11 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2024","cve_id":"44946","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-2024-44946","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2024-09-10T15:27:06.483265Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2024-09-12T17:33:16.399Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"},{"providerMetadata":{"dateUpdated":"2025-11-03T22:13:51.524Z","orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE"},"references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"},{"url":"https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html"}],"title":"CVE Program Container"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["include/net/kcm.h","net/kcm/kcmsock.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"8c9cdbf600143bd6835c8b8351e5ac956da79aec","status":"affected","version":"ab7ac4eb9832e32a09f4e8042705484d2fb0aad3","versionType":"git"},{"lessThan":"6633b17840bf828921254d788ccd15602843fe9b","status":"affected","version":"ab7ac4eb9832e32a09f4e8042705484d2fb0aad3","versionType":"git"},{"lessThan":"eb06c8d3022ce6738711191c89f9b3e9cfb91914","status":"affected","version":"ab7ac4eb9832e32a09f4e8042705484d2fb0aad3","versionType":"git"},{"lessThan":"fa6c23fe6dcac8c8bd63920ee8681292a2bd544e","status":"affected","version":"ab7ac4eb9832e32a09f4e8042705484d2fb0aad3","versionType":"git"},{"lessThan":"72da240aafb142630cf16adc803ccdacb3780849","status":"affected","version":"ab7ac4eb9832e32a09f4e8042705484d2fb0aad3","versionType":"git"},{"lessThan":"00425508f30baa5ab6449a1f478480ca7cffa6da","status":"affected","version":"ab7ac4eb9832e32a09f4e8042705484d2fb0aad3","versionType":"git"},{"lessThan":"9c8d544ed619f704e2b70e63e08ab75630c2ea23","status":"affected","version":"ab7ac4eb9832e32a09f4e8042705484d2fb0aad3","versionType":"git"},{"lessThan":"807067bf014d4a3ae2cc55bd3de16f22a01eb580","status":"affected","version":"ab7ac4eb9832e32a09f4e8042705484d2fb0aad3","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/net/kcm.h","net/kcm/kcmsock.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.6"},{"lessThan":"4.6","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"4.19.*","status":"unaffected","version":"4.19.321","versionType":"semver"},{"lessThanOrEqual":"5.4.*","status":"unaffected","version":"5.4.283","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.225","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.166","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.107","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.48","versionType":"semver"},{"lessThanOrEqual":"6.10.*","status":"unaffected","version":"6.10.7","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.11","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"4.19.321","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.4.283","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.225","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.166","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.107","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.48","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.10.7","versionStartIncluding":"4.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.11","versionStartIncluding":"4.6","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nkcm: Serialise kcm_sendmsg() for the same socket.\n\nsyzkaller reported UAF in kcm_release(). [0]\n\nThe scenario is\n\n  1. Thread A builds a skb with MSG_MORE and sets kcm->seq_skb.\n\n  2. Thread A resumes building skb from kcm->seq_skb but is blocked\n     by sk_stream_wait_memory()\n\n  3. Thread B calls sendmsg() concurrently, finishes building kcm->seq_skb\n     and puts the skb to the write queue\n\n  4. Thread A faces an error and finally frees skb that is already in the\n     write queue\n\n  5. kcm_release() does double-free the skb in the write queue\n\nWhen a thread is building a MSG_MORE skb, another thread must not touch it.\n\nLet's add a per-sk mutex and serialise kcm_sendmsg().\n\n[0]:\nBUG: KASAN: slab-use-after-free in __skb_unlink include/linux/skbuff.h:2366 [inline]\nBUG: KASAN: slab-use-after-free in __skb_dequeue include/linux/skbuff.h:2385 [inline]\nBUG: KASAN: slab-use-after-free in __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]\nBUG: KASAN: slab-use-after-free in __skb_queue_purge include/linux/skbuff.h:3181 [inline]\nBUG: KASAN: slab-use-after-free in kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691\nRead of size 8 at addr ffff0000ced0fc80 by task syz-executor329/6167\n\nCPU: 1 PID: 6167 Comm: syz-executor329 Tainted: G    B              6.8.0-rc5-syzkaller-g9abbc24128bc #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024\nCall trace:\n dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291\n show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x178/0x518 mm/kasan/report.c:488\n kasan_report+0xd8/0x138 mm/kasan/report.c:601\n __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381\n __skb_unlink include/linux/skbuff.h:2366 [inline]\n __skb_dequeue include/linux/skbuff.h:2385 [inline]\n __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]\n __skb_queue_purge include/linux/skbuff.h:3181 [inline]\n kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691\n __sock_release net/socket.c:659 [inline]\n sock_close+0xa4/0x1e8 net/socket.c:1421\n __fput+0x30c/0x738 fs/file_table.c:376\n ____fput+0x20/0x30 fs/file_table.c:404\n task_work_run+0x230/0x2e0 kernel/task_work.c:180\n exit_task_work include/linux/task_work.h:38 [inline]\n do_exit+0x618/0x1f64 kernel/exit.c:871\n do_group_exit+0x194/0x22c kernel/exit.c:1020\n get_signal+0x1500/0x15ec kernel/signal.c:2893\n do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249\n do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148\n exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]\n exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]\n el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713\n el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730\n el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598\n\nAllocated by task 6166:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x40/0x78 mm/kasan/common.c:68\n kasan_save_alloc_info+0x70/0x84 mm/kasan/generic.c:626\n unpoison_slab_object mm/kasan/common.c:314 [inline]\n __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:340\n kasan_slab_alloc include/linux/kasan.h:201 [inline]\n slab_post_alloc_hook mm/slub.c:3813 [inline]\n slab_alloc_node mm/slub.c:3860 [inline]\n kmem_cache_alloc_node+0x204/0x4c0 mm/slub.c:3903\n __alloc_skb+0x19c/0x3d8 net/core/skbuff.c:641\n alloc_skb include/linux/skbuff.h:1296 [inline]\n kcm_sendmsg+0x1d3c/0x2124 net/kcm/kcmsock.c:783\n sock_sendmsg_nosec net/socket.c:730 [inline]\n __sock_sendmsg net/socket.c:745 [inline]\n sock_sendmsg+0x220/0x2c0 net/socket.c:768\n splice_to_socket+0x7cc/0xd58 fs/splice.c:889\n do_splice_from fs/splice.c:941 [inline]\n direct_splice_actor+0xec/0x1d8 fs/splice.c:1164\n splice_direct_to_actor+0x438/0xa0c fs/splice.c:1108\n do_splice_direct_actor \n---truncated---"}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-08-04T09:30:21.856Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/8c9cdbf600143bd6835c8b8351e5ac956da79aec"},{"url":"https://git.kernel.org/stable/c/6633b17840bf828921254d788ccd15602843fe9b"},{"url":"https://git.kernel.org/stable/c/eb06c8d3022ce6738711191c89f9b3e9cfb91914"},{"url":"https://git.kernel.org/stable/c/fa6c23fe6dcac8c8bd63920ee8681292a2bd544e"},{"url":"https://git.kernel.org/stable/c/72da240aafb142630cf16adc803ccdacb3780849"},{"url":"https://git.kernel.org/stable/c/00425508f30baa5ab6449a1f478480ca7cffa6da"},{"url":"https://git.kernel.org/stable/c/9c8d544ed619f704e2b70e63e08ab75630c2ea23"},{"url":"https://git.kernel.org/stable/c/807067bf014d4a3ae2cc55bd3de16f22a01eb580"}],"title":"kcm: Serialise kcm_sendmsg() for the same socket.","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2024-44946","datePublished":"2024-08-31T13:22:47.250Z","dateReserved":"2024-08-21T05:34:56.665Z","dateUpdated":"2026-08-04T09:30:21.856Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2024-08-31 14:15:04","lastModifiedDate":"2026-08-04 11:20:02","problem_types":["CWE-416"],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9},{"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}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2024-09-10T15:27:06.483265Z","id":"CVE-2024-44946","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.6","versionEndExcluding":"6.1.107","matchCriteriaId":"90446753-6047-4C19-AD2D-8691C846DDB3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.48","matchCriteriaId":"9DE9201A-CE6B-4726-BABB-8265EA0F8AE4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.10.7","matchCriteriaId":"D2AFDFD1-D95A-4EB7-843B-5E7659518B67"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.11:rc1:*:*:*:*:*:*","matchCriteriaId":"8B3CE743-2126-47A3-8B7C-822B502CF119"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.11:rc2:*:*:*:*:*:*","matchCriteriaId":"4DEB27E7-30AA-45CC-8934-B89263EF3551"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.11:rc3:*:*:*:*:*:*","matchCriteriaId":"E0005AEF-856E-47EB-BFE4-90C46899394D"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.11:rc4:*:*:*:*:*:*","matchCriteriaId":"39889A68-6D34-47A6-82FC-CD0BF23D6754"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2024","CveId":"44946","Ordinal":"1","Title":"kcm: Serialise kcm_sendmsg() for the same socket.","CVE":"CVE-2024-44946","Year":"2024"},"notes":[{"CveYear":"2024","CveId":"44946","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nkcm: Serialise kcm_sendmsg() for the same socket.\n\nsyzkaller reported UAF in kcm_release(). [0]\n\nThe scenario is\n\n  1. Thread A builds a skb with MSG_MORE and sets kcm->seq_skb.\n\n  2. Thread A resumes building skb from kcm->seq_skb but is blocked\n     by sk_stream_wait_memory()\n\n  3. Thread B calls sendmsg() concurrently, finishes building kcm->seq_skb\n     and puts the skb to the write queue\n\n  4. Thread A faces an error and finally frees skb that is already in the\n     write queue\n\n  5. kcm_release() does double-free the skb in the write queue\n\nWhen a thread is building a MSG_MORE skb, another thread must not touch it.\n\nLet's add a per-sk mutex and serialise kcm_sendmsg().\n\n[0]:\nBUG: KASAN: slab-use-after-free in __skb_unlink include/linux/skbuff.h:2366 [inline]\nBUG: KASAN: slab-use-after-free in __skb_dequeue include/linux/skbuff.h:2385 [inline]\nBUG: KASAN: slab-use-after-free in __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]\nBUG: KASAN: slab-use-after-free in __skb_queue_purge include/linux/skbuff.h:3181 [inline]\nBUG: KASAN: slab-use-after-free in kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691\nRead of size 8 at addr ffff0000ced0fc80 by task syz-executor329/6167\n\nCPU: 1 PID: 6167 Comm: syz-executor329 Tainted: G    B              6.8.0-rc5-syzkaller-g9abbc24128bc #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024\nCall trace:\n dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291\n show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x178/0x518 mm/kasan/report.c:488\n kasan_report+0xd8/0x138 mm/kasan/report.c:601\n __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381\n __skb_unlink include/linux/skbuff.h:2366 [inline]\n __skb_dequeue include/linux/skbuff.h:2385 [inline]\n __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]\n __skb_queue_purge include/linux/skbuff.h:3181 [inline]\n kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691\n __sock_release net/socket.c:659 [inline]\n sock_close+0xa4/0x1e8 net/socket.c:1421\n __fput+0x30c/0x738 fs/file_table.c:376\n ____fput+0x20/0x30 fs/file_table.c:404\n task_work_run+0x230/0x2e0 kernel/task_work.c:180\n exit_task_work include/linux/task_work.h:38 [inline]\n do_exit+0x618/0x1f64 kernel/exit.c:871\n do_group_exit+0x194/0x22c kernel/exit.c:1020\n get_signal+0x1500/0x15ec kernel/signal.c:2893\n do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249\n do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148\n exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]\n exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]\n el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713\n el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730\n el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598\n\nAllocated by task 6166:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x40/0x78 mm/kasan/common.c:68\n kasan_save_alloc_info+0x70/0x84 mm/kasan/generic.c:626\n unpoison_slab_object mm/kasan/common.c:314 [inline]\n __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:340\n kasan_slab_alloc include/linux/kasan.h:201 [inline]\n slab_post_alloc_hook mm/slub.c:3813 [inline]\n slab_alloc_node mm/slub.c:3860 [inline]\n kmem_cache_alloc_node+0x204/0x4c0 mm/slub.c:3903\n __alloc_skb+0x19c/0x3d8 net/core/skbuff.c:641\n alloc_skb include/linux/skbuff.h:1296 [inline]\n kcm_sendmsg+0x1d3c/0x2124 net/kcm/kcmsock.c:783\n sock_sendmsg_nosec net/socket.c:730 [inline]\n __sock_sendmsg net/socket.c:745 [inline]\n sock_sendmsg+0x220/0x2c0 net/socket.c:768\n splice_to_socket+0x7cc/0xd58 fs/splice.c:889\n do_splice_from fs/splice.c:941 [inline]\n direct_splice_actor+0xec/0x1d8 fs/splice.c:1164\n splice_direct_to_actor+0x438/0xa0c fs/splice.c:1108\n do_splice_direct_actor \n---truncated---","Type":"Description","Title":"kcm: Serialise kcm_sendmsg() for the same socket."}]}}}