{"id":"CVE-2026-97594","state":"PUBLISHED","title":"landlock: Fix use-after-free of the source's parent directory","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nlandlock: Fix use-after-free of the source's parent directory\n\ncurrent_check_refer_path() reads old_dentry->d_parent without holding a\nreference nor a lock on it, and then dereferences it in\ncollect_domain_accesses() and in the audit record.\n\nA reference on a child does not pin its parent: __d_move() reassigns\ndentry->d_parent and drops the reference the child held on its former\nparent.  hook_path_rename() is not affected because the rename path\ncalls lock_rename() before the hook, so the source cannot be reparented\nunder it.  hook_path_link() has no such protection: filename_linkat()\nholds a reference on the source dentry but neither locks nor references\nits parent, so a concurrent rename(2) can reparent the source while\nsecurity_path_link() runs, and the former parent can then be removed and\nfreed while the hook walks it.\n\nA process can trigger this after entering a Landlock domain that handles\nat least one filesystem access right.  The process can then race a\nlinkat(2) loop against rename(2) and rmdir(2):\n\n  BUG: KASAN: slab-use-after-free in collect_domain_accesses+0x278/0x290\n  Read of size 4 at addr ffff888160bd53f4 by task llrepro2/549\n   collect_domain_accesses+0x278/0x290\n   current_check_refer_path+0x952/0x1120\n   security_path_link+0x1be/0x320\n   filename_linkat+0x342/0x6d0\n   __x64_sys_linkat+0xfa/0x150\n  Freed by task 562:\n   kmem_cache_free+0x139/0x4c0\n   i_callback+0x4b/0x80\n   rcu_core+0x7dc/0x10a0\n\nTake a reference on the dentry selected as the source parent, using\ndget() for the common-mount-root case and dget_parent() otherwise.\nRelease it after the hierarchy walk and synchronous audit logging.\n\n[mic: Clarify the caller, reachability, and reference handling]","publishedAt":"2026-09-25T10:22:10.548Z","updatedAt":"2026-10-30T12:37:31.781Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"0475440ff8c04be26a88733af0c85f597bb28c0a","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"48fc1c74052c956c59d5b16b5e18e0dd36b76aa2","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"4c37992b9668c4f37aae41dd95c369f7b6009915","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"379efd2ce8b26fd35feb13ccc2f671ff105a5052","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"ba29c46ccfe3ebadfb8aa18149186c49f84b14f8","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"2c6dc792538260a8087ac5b22c31b3b8e47c85d6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/landlock/fs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/landlock/fs.c"]}],"references":["https://git.kernel.org/stable/c/0475440ff8c04be26a88733af0c85f597bb28c0a","https://git.kernel.org/stable/c/48fc1c74052c956c59d5b16b5e18e0dd36b76aa2","https://git.kernel.org/stable/c/4c37992b9668c4f37aae41dd95c369f7b6009915","https://git.kernel.org/stable/c/379efd2ce8b26fd35feb13ccc2f671ff105a5052","https://git.kernel.org/stable/c/ba29c46ccfe3ebadfb8aa18149186c49f84b14f8","https://git.kernel.org/stable/c/2c6dc792538260a8087ac5b22c31b3b8e47c85d6"],"weaknesses":[],"ingestedAt":"2026-10-30T12:56:04.490Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/97xxx/CVE-2026-97594.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-97594","state":"PUBLISHED","datePublished":"2026-09-25T10:22:10.548Z","dateUpdated":"2026-10-30T12:37:31.781Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-24T16:01:01.157Z"},"containers":{"cna":{"title":"landlock: Fix use-after-free of the source's parent directory","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nlandlock: Fix use-after-free of the source's parent directory\n\ncurrent_check_refer_path() reads old_dentry->d_parent without holding a\nreference nor a lock on it, and then dereferences it in\ncollect_domain_accesses() and in the audit record.\n\nA reference on a child does not pin its parent: __d_move() reassigns\ndentry->d_parent and drops the reference the child held on its former\nparent.  hook_path_rename() is not affected because the rename path\ncalls lock_rename() before the hook, so the source cannot be reparented\nunder it.  hook_path_link() has no such protection: filename_linkat()\nholds a reference on the source dentry but neither locks nor references\nits parent, so a concurrent rename(2) can reparent the source while\nsecurity_path_link() runs, and the former parent can then be removed and\nfreed while the hook walks it.\n\nA process can trigger this after entering a Landlock domain that handles\nat least one filesystem access right.  The process can then race a\nlinkat(2) loop against rename(2) and rmdir(2):\n\n  BUG: KASAN: slab-use-after-free in collect_domain_accesses+0x278/0x290\n  Read of size 4 at addr ffff888160bd53f4 by task llrepro2/549\n   collect_domain_accesses+0x278/0x290\n   current_check_refer_path+0x952/0x1120\n   security_path_link+0x1be/0x320\n   filename_linkat+0x342/0x6d0\n   __x64_sys_linkat+0xfa/0x150\n  Freed by task 562:\n   kmem_cache_free+0x139/0x4c0\n   i_callback+0x4b/0x80\n   rcu_core+0x7dc/0x10a0\n\nTake a reference on the dentry selected as the source parent, using\ndget() for the common-mount-root case and dget_parent() otherwise.\nRelease it after the hierarchy walk and synchronous audit logging.\n\n[mic: Clarify the caller, reachability, and reference handling]"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"0475440ff8c04be26a88733af0c85f597bb28c0a","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"48fc1c74052c956c59d5b16b5e18e0dd36b76aa2","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"4c37992b9668c4f37aae41dd95c369f7b6009915","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"379efd2ce8b26fd35feb13ccc2f671ff105a5052","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"ba29c46ccfe3ebadfb8aa18149186c49f84b14f8","versionType":"git"},{"version":"b91c3e4ea756b12b7d992529226edce1cfd854d7","status":"affected","lessThan":"2c6dc792538260a8087ac5b22c31b3b8e47c85d6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/landlock/fs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.19","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.19","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/landlock/fs.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0475440ff8c04be26a88733af0c85f597bb28c0a"},{"url":"https://git.kernel.org/stable/c/48fc1c74052c956c59d5b16b5e18e0dd36b76aa2"},{"url":"https://git.kernel.org/stable/c/4c37992b9668c4f37aae41dd95c369f7b6009915"},{"url":"https://git.kernel.org/stable/c/379efd2ce8b26fd35feb13ccc2f671ff105a5052"},{"url":"https://git.kernel.org/stable/c/ba29c46ccfe3ebadfb8aa18149186c49f84b14f8"},{"url":"https://git.kernel.org/stable/c/2c6dc792538260a8087ac5b22c31b3b8e47c85d6"}],"metrics":[{"cvssV3_1":{"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"},"scenarios":[{"lang":"en","value":"AV:L - The trigger is a local linkat(2) syscall: filename_linkat() -> security_path_link() -> hook_path_link() -> current_check_refer_path(), raced against local rename(2)/rmdir(2). No remote protocol supplies any of the input.\nAC:L - The attacker runs every side of the race: a linkat() loop on their own file, plus rename() to reparent the source and rmdir() to free the old parent, all in directories they create (e.g. /tmp). No condition outside the attacker's control is needed; the window can be retried at will.\nPR:L - An ordinary unprivileged user can enter a Landlock domain that handles any FS right (landlock_create_ruleset + landlock_restrict_self after PR_SET_NO_NEW_PRIVS, no capability needed); that makes landlock_get_applicable_subject() non-NULL and reaches the unpinned d_parent read.\nUI:N - The attacker's own syscalls on files and directories they own trigger the bug; no other user or administrator has to do anything.\nS:U - The corruption happens in kernel memory under the same kernel authority; exploiting it is standard local privilege escalation, not a crossing into a separate authority such as a hypervisor.\nC:H - collect_domain_accesses() dereferences the freed old_parent dentry and follows its d_parent/d_inode pointers into the Landlock inode blob via find_rule(). If the attacker reallocates the freed slab, they control pointers that the kernel then follows and reads.\nI:H - collect_domain_accesses() calls dget() and later dput() on the freed dentry. That writes the lockref inside the freed or reallocated object and can run dentry teardown on it, a write primitive that can lead to a double free or control-flow hijack.\nA:H - The KASAN report in the commit shows a slab use-after-free in collect_domain_accesses(). On production kernels the refcount changes on freed memory or the stale pointer walk can oops or panic the kernel."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:37:31.781Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}