CVE-2026-80928

Summary

In the Linux kernel, the following vulnerability has been resolved:

smack: fix cred UAF in smack_file_send_sigiotask()

When inspecting the credentials of another task, objective credentials (->real_cred, accessed with __task_cred()) must always be used.

Accessing ->cred on a non-current task is forbidden unless that task is being created or destroyed; a task is allowed to change its own ->cred pointer with no synchronization, and changing ->cred should only affect the current syscall.

smack_file_send_sigiotask() was accessing both sets of credentials: First tsk->cred, then __task_cred(tsk).

Fix it, always access the objective credentials here.

I have tested that this bug can lead to a KASAN-reported UAF of struct cred in smack_file_send_sigiotask(), and that this fix prevents the race.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux3b11a1decef07c19443d24ae926982bc8ec9f4c0 < a512366d84e134a9eefc2cc40eeb6e80e2ec162caffected
LinuxLinux3b11a1decef07c19443d24ae926982bc8ec9f4c0 < 7c7fe043f3099d0d35002b248967f75e55345b93affected
LinuxLinux3b11a1decef07c19443d24ae926982bc8ec9f4c0 < f9c7b1f2b9d8f4176d2632743f51400855978aceaffected
LinuxLinux3b11a1decef07c19443d24ae926982bc8ec9f4c0 < b5bcf3adfa27279da4401ab8f1e1a706601a92beaffected
LinuxLinux3b11a1decef07c19443d24ae926982bc8ec9f4c0 < ed64aa505875a3b4defd504ee8e59e1949246a62affected
LinuxLinux3b11a1decef07c19443d24ae926982bc8ec9f4c0 < b791401bf389a1546a830d2b381ca60fe94c7870affected
LinuxLinux3b11a1decef07c19443d24ae926982bc8ec9f4c0 < fedc88e38ce979a720cd2de042578cb5df3dc8deaffected
LinuxLinux2.6.29affected
LinuxLinux0 < 2.6.29unaffected
LinuxLinux5.15.221 <= 5.15.*unaffected
LinuxLinux6.1.188 <= 6.1.*unaffected
LinuxLinux6.6.157 <= 6.6.*unaffected
LinuxLinux6.12.109 <= 6.12.*unaffected
LinuxLinux6.18.50 <= 6.18.*unaffected
LinuxLinux7.2.4 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References