{"api_version":"1","generated_at":"2026-05-30T05:32:01+00:00","cve":"CVE-2026-46116","urls":{"html":"https://cve.report/CVE-2026-46116","api":"https://cve.report/api/cve/CVE-2026-46116.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-46116","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-46116"},"summary":{"title":"xfrm: defensively unhash xfrm_state lists in __xfrm_state_delete","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: defensively unhash xfrm_state lists in __xfrm_state_delete\n\nKASAN reproduces a slab-use-after-free in __xfrm_state_delete()'s\nhlist_del_rcu calls under syzkaller load on linux-6.12.y stable\n(reproduced on 6.12.47, also reachable via the same code path on\ntorvalds/master and on the ipsec tree). Nine unique signatures cluster\nin the xfrm_state lifecycle, the load-bearing one being:\n\n  BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:990 [inline]\n  BUG: KASAN: slab-use-after-free in hlist_del_rcu include/linux/rculist.h:516 [inline]\n  BUG: KASAN: slab-use-after-free in __xfrm_state_delete net/xfrm/xfrm_state.c\n  Write of size 8 at addr ffff8881198bcb70 by task kworker/u8:9/435\n\n  Workqueue: netns cleanup_net\n  Call Trace:\n   __hlist_del / hlist_del_rcu\n   __xfrm_state_delete\n   xfrm_state_delete\n   xfrm_state_flush\n   xfrm_state_fini\n   ops_exit_list\n   cleanup_net\n\nThe other observed signatures hit the same slab object from\n__xfrm_state_lookup, xfrm_alloc_spi, __xfrm_state_insert and an OOB\nwrite variant of __xfrm_state_delete, all on the byseq/byspi\nhash chains.\n\n__xfrm_state_delete() guards its byseq and byspi unhashes with\nvalue-based predicates:\n\n\tif (x->km.seq)\n\t\thlist_del_rcu(&x->byseq);\n\tif (x->id.spi)\n\t\thlist_del_rcu(&x->byspi);\n\nwhile everywhere else in the file (e.g. state_cache, state_cache_input)\nthe safer hlist_unhashed() check is used. xfrm_alloc_spi() sets\nx->id.spi = newspi inside xfrm_state_lock and then immediately inserts\ninto byspi, but a path that observes x->id.spi != 0 outside of\nxfrm_state_lock can still skip-or-hit the byspi unhash inconsistently\nwith whether x is actually on the list. The same holds for x->km.seq\nversus byseq, and the bydst/bysrc unhashes have no predicate at all,\nso a second __xfrm_state_delete() on the same object writes through\nLIST_POISON pprev.\n\nThe defensive change here:\n\n  - Use hlist_del_init_rcu() instead of hlist_del_rcu() on bydst,\n    bysrc, byseq and byspi so a second deletion is a no-op rather\n    than a write through LIST_POISON pprev. The byseq/byspi nodes\n    are already initialised in xfrm_state_alloc().\n  - Test hlist_unhashed() rather than the value predicate for\n    byseq/byspi, so the unhash decision tracks list state rather than\n    mutable scalar fields.\n\nEmpirical verification: applied this patch on top of v6.12.47, rebuilt,\nand re-ran the same syzkaller harness for 1h16m on a previously-crashy\nconfiguration that produced ~100 hits each of slab-use-after-free\nRead in xfrm_alloc_spi / Read in __xfrm_state_lookup / Write in\n__xfrm_state_delete. After the patch, 7.1M execs across 32 VMs at\n~1550 exec/sec produced zero xfrm_state UAF/OOB hits. /proc/slabinfo\nconfirms the xfrm_state slab is actively allocated and freed during\nthe run (~143 KiB resident), so the fuzzer is still exercising those\ncode paths -- they just no longer crash.\n\nReproduction:\n\n  - Linux 6.12.47 x86_64 + KASAN_GENERIC + KASAN_INLINE + KCOV\n  - syzkaller @ 746545b8b1e4c3a128db8652b340d3df90ce61db\n  - 32 QEMU/KVM VMs x 2 vCPU on AWS c5.metal bare metal\n  - 9 unique signatures collected in ~9h, all within xfrm_state\n    lifecycle","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-28 10:16:27","updated_at":"2026-05-28 13:44:01"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/a2e2d08fb070fab4947447171f1c4e3ca5a188e5","name":"https://git.kernel.org/stable/c/a2e2d08fb070fab4947447171f1c4e3ca5a188e5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/26edb0a3c99f9d958c212be68b21f1221614dcf0","name":"https://git.kernel.org/stable/c/26edb0a3c99f9d958c212be68b21f1221614dcf0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4980162de555cb838f1a189ce7d2cbf5d2e7b050","name":"https://git.kernel.org/stable/c/4980162de555cb838f1a189ce7d2cbf5d2e7b050","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/14acf9652e5690de3c7486c6db5fb8dafd0a32a3","name":"https://git.kernel.org/stable/c/14acf9652e5690de3c7486c6db5fb8dafd0a32a3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b4a53add2fa8f1b5aa17d4c5686c320785fab182","name":"https://git.kernel.org/stable/c/b4a53add2fa8f1b5aa17d4c5686c320785fab182","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-46116","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46116","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7b4dc3600e4877178ba94c7fbf7e520421378aa6 b4a53add2fa8f1b5aa17d4c5686c320785fab182 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7b4dc3600e4877178ba94c7fbf7e520421378aa6 26edb0a3c99f9d958c212be68b21f1221614dcf0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7b4dc3600e4877178ba94c7fbf7e520421378aa6 4980162de555cb838f1a189ce7d2cbf5d2e7b050 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7b4dc3600e4877178ba94c7fbf7e520421378aa6 a2e2d08fb070fab4947447171f1c4e3ca5a188e5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7b4dc3600e4877178ba94c7fbf7e520421378aa6 14acf9652e5690de3c7486c6db5fb8dafd0a32a3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.19","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.140 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.88 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.30 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.7 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1-rc3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"46116","cve":"CVE-2026-46116","epss":"0.000180000","percentile":"0.051640000","score_date":"2026-05-29","updated_at":"2026-05-30 00:13:24"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/xfrm/xfrm_state.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"b4a53add2fa8f1b5aa17d4c5686c320785fab182","status":"affected","version":"7b4dc3600e4877178ba94c7fbf7e520421378aa6","versionType":"git"},{"lessThan":"26edb0a3c99f9d958c212be68b21f1221614dcf0","status":"affected","version":"7b4dc3600e4877178ba94c7fbf7e520421378aa6","versionType":"git"},{"lessThan":"4980162de555cb838f1a189ce7d2cbf5d2e7b050","status":"affected","version":"7b4dc3600e4877178ba94c7fbf7e520421378aa6","versionType":"git"},{"lessThan":"a2e2d08fb070fab4947447171f1c4e3ca5a188e5","status":"affected","version":"7b4dc3600e4877178ba94c7fbf7e520421378aa6","versionType":"git"},{"lessThan":"14acf9652e5690de3c7486c6db5fb8dafd0a32a3","status":"affected","version":"7b4dc3600e4877178ba94c7fbf7e520421378aa6","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/xfrm/xfrm_state.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.19"},{"lessThan":"2.6.19","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.140","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.88","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.30","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.7","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1-rc3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.140","versionStartIncluding":"2.6.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.88","versionStartIncluding":"2.6.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.30","versionStartIncluding":"2.6.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.7","versionStartIncluding":"2.6.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1-rc3","versionStartIncluding":"2.6.19","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: defensively unhash xfrm_state lists in __xfrm_state_delete\n\nKASAN reproduces a slab-use-after-free in __xfrm_state_delete()'s\nhlist_del_rcu calls under syzkaller load on linux-6.12.y stable\n(reproduced on 6.12.47, also reachable via the same code path on\ntorvalds/master and on the ipsec tree). Nine unique signatures cluster\nin the xfrm_state lifecycle, the load-bearing one being:\n\n  BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:990 [inline]\n  BUG: KASAN: slab-use-after-free in hlist_del_rcu include/linux/rculist.h:516 [inline]\n  BUG: KASAN: slab-use-after-free in __xfrm_state_delete net/xfrm/xfrm_state.c\n  Write of size 8 at addr ffff8881198bcb70 by task kworker/u8:9/435\n\n  Workqueue: netns cleanup_net\n  Call Trace:\n   __hlist_del / hlist_del_rcu\n   __xfrm_state_delete\n   xfrm_state_delete\n   xfrm_state_flush\n   xfrm_state_fini\n   ops_exit_list\n   cleanup_net\n\nThe other observed signatures hit the same slab object from\n__xfrm_state_lookup, xfrm_alloc_spi, __xfrm_state_insert and an OOB\nwrite variant of __xfrm_state_delete, all on the byseq/byspi\nhash chains.\n\n__xfrm_state_delete() guards its byseq and byspi unhashes with\nvalue-based predicates:\n\n\tif (x->km.seq)\n\t\thlist_del_rcu(&x->byseq);\n\tif (x->id.spi)\n\t\thlist_del_rcu(&x->byspi);\n\nwhile everywhere else in the file (e.g. state_cache, state_cache_input)\nthe safer hlist_unhashed() check is used. xfrm_alloc_spi() sets\nx->id.spi = newspi inside xfrm_state_lock and then immediately inserts\ninto byspi, but a path that observes x->id.spi != 0 outside of\nxfrm_state_lock can still skip-or-hit the byspi unhash inconsistently\nwith whether x is actually on the list. The same holds for x->km.seq\nversus byseq, and the bydst/bysrc unhashes have no predicate at all,\nso a second __xfrm_state_delete() on the same object writes through\nLIST_POISON pprev.\n\nThe defensive change here:\n\n  - Use hlist_del_init_rcu() instead of hlist_del_rcu() on bydst,\n    bysrc, byseq and byspi so a second deletion is a no-op rather\n    than a write through LIST_POISON pprev. The byseq/byspi nodes\n    are already initialised in xfrm_state_alloc().\n  - Test hlist_unhashed() rather than the value predicate for\n    byseq/byspi, so the unhash decision tracks list state rather than\n    mutable scalar fields.\n\nEmpirical verification: applied this patch on top of v6.12.47, rebuilt,\nand re-ran the same syzkaller harness for 1h16m on a previously-crashy\nconfiguration that produced ~100 hits each of slab-use-after-free\nRead in xfrm_alloc_spi / Read in __xfrm_state_lookup / Write in\n__xfrm_state_delete. After the patch, 7.1M execs across 32 VMs at\n~1550 exec/sec produced zero xfrm_state UAF/OOB hits. /proc/slabinfo\nconfirms the xfrm_state slab is actively allocated and freed during\nthe run (~143 KiB resident), so the fuzzer is still exercising those\ncode paths -- they just no longer crash.\n\nReproduction:\n\n  - Linux 6.12.47 x86_64 + KASAN_GENERIC + KASAN_INLINE + KCOV\n  - syzkaller @ 746545b8b1e4c3a128db8652b340d3df90ce61db\n  - 32 QEMU/KVM VMs x 2 vCPU on AWS c5.metal bare metal\n  - 9 unique signatures collected in ~9h, all within xfrm_state\n    lifecycle"}],"providerMetadata":{"dateUpdated":"2026-05-28T09:35:30.689Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/b4a53add2fa8f1b5aa17d4c5686c320785fab182"},{"url":"https://git.kernel.org/stable/c/26edb0a3c99f9d958c212be68b21f1221614dcf0"},{"url":"https://git.kernel.org/stable/c/4980162de555cb838f1a189ce7d2cbf5d2e7b050"},{"url":"https://git.kernel.org/stable/c/a2e2d08fb070fab4947447171f1c4e3ca5a188e5"},{"url":"https://git.kernel.org/stable/c/14acf9652e5690de3c7486c6db5fb8dafd0a32a3"}],"title":"xfrm: defensively unhash xfrm_state lists in __xfrm_state_delete","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-46116","datePublished":"2026-05-28T09:35:30.689Z","dateReserved":"2026-05-13T15:03:33.098Z","dateUpdated":"2026-05-28T09:35:30.689Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-28 10:16:27","lastModifiedDate":"2026-05-28 13:44:01","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"46116","Ordinal":"1","Title":"xfrm: defensively unhash xfrm_state lists in __xfrm_state_delete","CVE":"CVE-2026-46116","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"46116","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: defensively unhash xfrm_state lists in __xfrm_state_delete\n\nKASAN reproduces a slab-use-after-free in __xfrm_state_delete()'s\nhlist_del_rcu calls under syzkaller load on linux-6.12.y stable\n(reproduced on 6.12.47, also reachable via the same code path on\ntorvalds/master and on the ipsec tree). Nine unique signatures cluster\nin the xfrm_state lifecycle, the load-bearing one being:\n\n  BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:990 [inline]\n  BUG: KASAN: slab-use-after-free in hlist_del_rcu include/linux/rculist.h:516 [inline]\n  BUG: KASAN: slab-use-after-free in __xfrm_state_delete net/xfrm/xfrm_state.c\n  Write of size 8 at addr ffff8881198bcb70 by task kworker/u8:9/435\n\n  Workqueue: netns cleanup_net\n  Call Trace:\n   __hlist_del / hlist_del_rcu\n   __xfrm_state_delete\n   xfrm_state_delete\n   xfrm_state_flush\n   xfrm_state_fini\n   ops_exit_list\n   cleanup_net\n\nThe other observed signatures hit the same slab object from\n__xfrm_state_lookup, xfrm_alloc_spi, __xfrm_state_insert and an OOB\nwrite variant of __xfrm_state_delete, all on the byseq/byspi\nhash chains.\n\n__xfrm_state_delete() guards its byseq and byspi unhashes with\nvalue-based predicates:\n\n\tif (x->km.seq)\n\t\thlist_del_rcu(&x->byseq);\n\tif (x->id.spi)\n\t\thlist_del_rcu(&x->byspi);\n\nwhile everywhere else in the file (e.g. state_cache, state_cache_input)\nthe safer hlist_unhashed() check is used. xfrm_alloc_spi() sets\nx->id.spi = newspi inside xfrm_state_lock and then immediately inserts\ninto byspi, but a path that observes x->id.spi != 0 outside of\nxfrm_state_lock can still skip-or-hit the byspi unhash inconsistently\nwith whether x is actually on the list. The same holds for x->km.seq\nversus byseq, and the bydst/bysrc unhashes have no predicate at all,\nso a second __xfrm_state_delete() on the same object writes through\nLIST_POISON pprev.\n\nThe defensive change here:\n\n  - Use hlist_del_init_rcu() instead of hlist_del_rcu() on bydst,\n    bysrc, byseq and byspi so a second deletion is a no-op rather\n    than a write through LIST_POISON pprev. The byseq/byspi nodes\n    are already initialised in xfrm_state_alloc().\n  - Test hlist_unhashed() rather than the value predicate for\n    byseq/byspi, so the unhash decision tracks list state rather than\n    mutable scalar fields.\n\nEmpirical verification: applied this patch on top of v6.12.47, rebuilt,\nand re-ran the same syzkaller harness for 1h16m on a previously-crashy\nconfiguration that produced ~100 hits each of slab-use-after-free\nRead in xfrm_alloc_spi / Read in __xfrm_state_lookup / Write in\n__xfrm_state_delete. After the patch, 7.1M execs across 32 VMs at\n~1550 exec/sec produced zero xfrm_state UAF/OOB hits. /proc/slabinfo\nconfirms the xfrm_state slab is actively allocated and freed during\nthe run (~143 KiB resident), so the fuzzer is still exercising those\ncode paths -- they just no longer crash.\n\nReproduction:\n\n  - Linux 6.12.47 x86_64 + KASAN_GENERIC + KASAN_INLINE + KCOV\n  - syzkaller @ 746545b8b1e4c3a128db8652b340d3df90ce61db\n  - 32 QEMU/KVM VMs x 2 vCPU on AWS c5.metal bare metal\n  - 9 unique signatures collected in ~9h, all within xfrm_state\n    lifecycle","Type":"Description","Title":"xfrm: defensively unhash xfrm_state lists in __xfrm_state_delete"}]}}}