{"id":"CVE-2026-80928","state":"PUBLISHED","title":"smack: fix cred UAF in smack_file_send_sigiotask()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmack: fix cred UAF in smack_file_send_sigiotask()\n\nWhen inspecting the credentials of another task, objective credentials\n(->real_cred, accessed with __task_cred()) must always be used.\n\nAccessing ->cred on a non-current task is forbidden unless that task is\nbeing created or destroyed; a task is allowed to change its own ->cred\npointer with no synchronization, and changing ->cred should only affect the\ncurrent syscall.\n\nsmack_file_send_sigiotask() was accessing both sets of credentials: First\ntsk->cred, then __task_cred(tsk).\n\nFix it, always access the objective credentials here.\n\nI have tested that this bug can lead to a KASAN-reported UAF of struct cred\nin smack_file_send_sigiotask(), and that this fix prevents the race.","publishedAt":"2026-09-11T19:42:04.044Z","updatedAt":"2026-10-19T08:45:12.134Z","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":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"a512366d84e134a9eefc2cc40eeb6e80e2ec162c","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"7c7fe043f3099d0d35002b248967f75e55345b93","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"f9c7b1f2b9d8f4176d2632743f51400855978ace","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"b5bcf3adfa27279da4401ab8f1e1a706601a92be","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"ed64aa505875a3b4defd504ee8e59e1949246a62","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"b791401bf389a1546a830d2b381ca60fe94c7870","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"fedc88e38ce979a720cd2de042578cb5df3dc8de","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/smack/smack_lsm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.29","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.29","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.109","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","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/smack/smack_lsm.c"]}],"references":["https://git.kernel.org/stable/c/a512366d84e134a9eefc2cc40eeb6e80e2ec162c","https://git.kernel.org/stable/c/7c7fe043f3099d0d35002b248967f75e55345b93","https://git.kernel.org/stable/c/f9c7b1f2b9d8f4176d2632743f51400855978ace","https://git.kernel.org/stable/c/b5bcf3adfa27279da4401ab8f1e1a706601a92be","https://git.kernel.org/stable/c/ed64aa505875a3b4defd504ee8e59e1949246a62","https://git.kernel.org/stable/c/b791401bf389a1546a830d2b381ca60fe94c7870","https://git.kernel.org/stable/c/fedc88e38ce979a720cd2de042578cb5df3dc8de"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/80xxx/CVE-2026-80928.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80928","state":"PUBLISHED","datePublished":"2026-09-11T19:42:04.044Z","dateUpdated":"2026-10-19T08:45:12.134Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.802Z"},"containers":{"cna":{"title":"smack: fix cred UAF in smack_file_send_sigiotask()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmack: fix cred UAF in smack_file_send_sigiotask()\n\nWhen inspecting the credentials of another task, objective credentials\n(->real_cred, accessed with __task_cred()) must always be used.\n\nAccessing ->cred on a non-current task is forbidden unless that task is\nbeing created or destroyed; a task is allowed to change its own ->cred\npointer with no synchronization, and changing ->cred should only affect the\ncurrent syscall.\n\nsmack_file_send_sigiotask() was accessing both sets of credentials: First\ntsk->cred, then __task_cred(tsk).\n\nFix it, always access the objective credentials here.\n\nI have tested that this bug can lead to a KASAN-reported UAF of struct cred\nin smack_file_send_sigiotask(), and that this fix prevents the race."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"a512366d84e134a9eefc2cc40eeb6e80e2ec162c","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"7c7fe043f3099d0d35002b248967f75e55345b93","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"f9c7b1f2b9d8f4176d2632743f51400855978ace","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"b5bcf3adfa27279da4401ab8f1e1a706601a92be","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"ed64aa505875a3b4defd504ee8e59e1949246a62","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"b791401bf389a1546a830d2b381ca60fe94c7870","versionType":"git"},{"version":"3b11a1decef07c19443d24ae926982bc8ec9f4c0","status":"affected","lessThan":"fedc88e38ce979a720cd2de042578cb5df3dc8de","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/smack/smack_lsm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.29","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.29","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.109","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.50","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","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/smack/smack_lsm.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a512366d84e134a9eefc2cc40eeb6e80e2ec162c"},{"url":"https://git.kernel.org/stable/c/7c7fe043f3099d0d35002b248967f75e55345b93"},{"url":"https://git.kernel.org/stable/c/f9c7b1f2b9d8f4176d2632743f51400855978ace"},{"url":"https://git.kernel.org/stable/c/b5bcf3adfa27279da4401ab8f1e1a706601a92be"},{"url":"https://git.kernel.org/stable/c/ed64aa505875a3b4defd504ee8e59e1949246a62"},{"url":"https://git.kernel.org/stable/c/b791401bf389a1546a830d2b381ca60fe94c7870"},{"url":"https://git.kernel.org/stable/c/fedc88e38ce979a720cd2de042578cb5df3dc8de"}],"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 - Reachable only via local syscalls: fcntl(F_SETOWN)/O_ASYNC on a pipe or socket, then write or MSG_OOB so kill_fasync()/send_sigurg() call smack_file_send_sigiotask(). Same SIGIO path as CVE-2026-72183 (AV:L); a remote peer can raise SIGIO only on a socket the local attacker already owns.\nAC:L - The attacker controls both sides of the race: one thread loops faccessat() so access_override_creds() installs a non_rcu subjective cred that revert_creds()+put_cred() frees without RCU, while another thread writes the pipe or sends OOB to fire SIGIO. The fix author reproduced a KASAN cred UAF; the window is retryable.\nPR:L - pipe(), fcntl(F_SETOWN/F_SETFL), write(), and faccessat() need no capabilities. An unprivileged user namespace (unshare(CLONE_NEWUSER)) makes access() install the non_rcu override (non-root uid with caps, or real uid != fsuid). The UAF is kernel cred memory on the attacker’s own task.\nUI:N - No victim action is required. The attacker arms fowner on their own file, overrides their own subjective creds via faccessat(), and triggers SIGIO themselves.\nS:U - This is in-kernel cred use-after-free leading to local privilege escalation within the kernel security authority. It is not a VM escape, IOMMU bypass, or userspace sandbox boundary crossing.\nC:H - This is a use-after-free of struct cred. After free, the cred slab can be sprayed so cred->security and the derived smack_known are attacker-controlled, enabling arbitrary kernel reads through smk_access() and smack_log(). Kernel UAF scores C:H.\nI:H - The same sprayed cred/task_smack/smack_known objects yield a fake-object primitive on the SIGIO path, exploitable for control-flow hijacking and arbitrary write as with other kernel cred UAFs. Kernel UAF scores I:H.\nA:H - The fix author confirmed a KASAN use-after-free of struct cred in smack_file_send_sigiotask(). Dereferencing the freed cred on the SIGIO path, including from kill_fasync() in interrupt context, causes a kernel oops or panic."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:45:12.134Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}