{"id":"CVE-2026-68149","state":"PUBLISHED","title":"fs: preserve ACL_DONT_CACHE state in forget_cached_acl()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs: preserve ACL_DONT_CACHE state in forget_cached_acl()\n\nThe ACL_DONT_CACHE state is meant to be a constant state for the inode\nfor filesystems that want to opt out of posix acl caching.\n\nCommit facd61053cff1 (\"fuse: fixes after adapting to new posix acl api\")\nused this facility to opt out of posix acl caching for fuse inodes with\nfuse server that does not negotiate FUSE_POSIX_ACL (fc->posix_acl).\n\nThe commit also takes care to gate the forget_all_cached_acls() call in\nfuse_set_acl() on fc->posix_acl because there is no need for it, but\nthere are other placed in fuse code which call forget_all_cached_acls()\nunconditional to fc->posix_acl and those cause the loss of the\nACL_DONT_CACHE state.\n\nThis is not only a functional bug. Properly timed, a get_acl() from this\nfuse filesystem can return a stale cached value, as was observed in tests,\nbecause set_acl() does not invalidate the unintentional acl cache.\n\nWe could fix this in fuse, but it actually makes no sense for the vfs\nhelper forget_cached_acl() to invalidate the ACL_DONT_CACHE state, so\nlet it not do that to fix fuse and future users of ACL_DONT_CACHE.","publishedAt":"2026-08-10T11:59:14.645Z","updatedAt":"2026-10-19T20:58:54.165Z","severity":{"score":8.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"b98fad81f1202b0eb26aacf3ff4cc7a21ed3b5bf","versionType":"git"},{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"834ddf899484a2f23129080e8773bc04f4691d07","versionType":"git"},{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"a019b074903b3ad0a9726087efd0e8291452023b","versionType":"git"},{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"ca03a7984a34f48085fd013e0d2cf4e6420b4acf","versionType":"git"},{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"4b9a5458d02e214ef2b384124ca626e3e381d778","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/posix_acl.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/posix_acl.c"]}],"references":["https://git.kernel.org/stable/c/b98fad81f1202b0eb26aacf3ff4cc7a21ed3b5bf","https://git.kernel.org/stable/c/834ddf899484a2f23129080e8773bc04f4691d07","https://git.kernel.org/stable/c/a019b074903b3ad0a9726087efd0e8291452023b","https://git.kernel.org/stable/c/ca03a7984a34f48085fd013e0d2cf4e6420b4acf","https://git.kernel.org/stable/c/4b9a5458d02e214ef2b384124ca626e3e381d778"],"weaknesses":["CWE-662"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/68xxx/CVE-2026-68149.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68149","state":"PUBLISHED","datePublished":"2026-08-10T11:59:14.645Z","dateUpdated":"2026-10-19T20:58:54.165Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-30T09:28:09.371Z"},"containers":{"cna":{"title":"fs: preserve ACL_DONT_CACHE state in forget_cached_acl()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs: preserve ACL_DONT_CACHE state in forget_cached_acl()\n\nThe ACL_DONT_CACHE state is meant to be a constant state for the inode\nfor filesystems that want to opt out of posix acl caching.\n\nCommit facd61053cff1 (\"fuse: fixes after adapting to new posix acl api\")\nused this facility to opt out of posix acl caching for fuse inodes with\nfuse server that does not negotiate FUSE_POSIX_ACL (fc->posix_acl).\n\nThe commit also takes care to gate the forget_all_cached_acls() call in\nfuse_set_acl() on fc->posix_acl because there is no need for it, but\nthere are other placed in fuse code which call forget_all_cached_acls()\nunconditional to fc->posix_acl and those cause the loss of the\nACL_DONT_CACHE state.\n\nThis is not only a functional bug. Properly timed, a get_acl() from this\nfuse filesystem can return a stale cached value, as was observed in tests,\nbecause set_acl() does not invalidate the unintentional acl cache.\n\nWe could fix this in fuse, but it actually makes no sense for the vfs\nhelper forget_cached_acl() to invalidate the ACL_DONT_CACHE state, so\nlet it not do that to fix fuse and future users of ACL_DONT_CACHE."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"b98fad81f1202b0eb26aacf3ff4cc7a21ed3b5bf","versionType":"git"},{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"834ddf899484a2f23129080e8773bc04f4691d07","versionType":"git"},{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"a019b074903b3ad0a9726087efd0e8291452023b","versionType":"git"},{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"ca03a7984a34f48085fd013e0d2cf4e6420b4acf","versionType":"git"},{"version":"facd61053cff100973921d4d45d47cf53c747ec6","status":"affected","lessThan":"4b9a5458d02e214ef2b384124ca626e3e381d778","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/posix_acl.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/posix_acl.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b98fad81f1202b0eb26aacf3ff4cc7a21ed3b5bf"},{"url":"https://git.kernel.org/stable/c/834ddf899484a2f23129080e8773bc04f4691d07"},{"url":"https://git.kernel.org/stable/c/a019b074903b3ad0a9726087efd0e8291452023b"},{"url":"https://git.kernel.org/stable/c/ca03a7984a34f48085fd013e0d2cf4e6420b4acf"},{"url":"https://git.kernel.org/stable/c/4b9a5458d02e214ef2b384124ca626e3e381d778"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","baseScore":8.4,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires local VFS syscalls (getxattr, statx, open, read, write) on a FUSE-backed mount; the bug is in kernel ACL caching, not in a network protocol handler.\nAC:L - The attacker controls the full trigger sequence (stat/getattr to clear ACL_DONT_CACHE, getxattr to populate cache, ACL change, then access) and can drive timing with concurrent threads without depending on uncontrollable system state.\nPR:L - Any unprivileged local user who can mount or access a FUSE filesystem (fusermount, user namespaces, virtio-fs/SSHFS mounts with allow_other) can reach the vulnerable code paths on files within that mount.\nUI:N - Exploitation is fully attacker-driven through syscall sequences on the FUSE mount; no victim click, mount action, or other interactive cooperation is required beyond routine filesystem use.\nS:C - On virtio-fs/Kata/Firecracker shared host directories, stale kernel ACL enforcement can let a guest/container process access host-exported files beyond the permissions the host administrator intended, crossing that isolation boundary.\nC:H - Stale permissive cached ACLs cause check_acl()/posix_acl_permission() to authorize reads of files that should be denied after ACL tightening, enabling unauthorized disclosure of protected file contents on default_permissions mounts.\nI:H - The same stale ACL bypass lets an attacker obtain write permission enforced by the kernel VFS on files whose ACLs were subsequently restricted, enabling unauthorized modification of protected data.\nA:N - This is a stale-cache logic bug with no memory corruption, kernel crash, panic, or hang; observed impact is incorrect ACL enforcement and authorization bypass, not availability loss."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:59:43.618Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-68149","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:44:54.722688Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-662","lang":"en","type":"CWE","description":"CWE-662 Improper Synchronization"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:58:54.165Z"}}]}}}