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
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b5bcf3adfa27279da4401ab8f1e1a706601a92beaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ed64aa505875a3b4defd504ee8e59e1949246a62affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b791401bf389a1546a830d2b381ca60fe94c7870affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < fedc88e38ce979a720cd2de042578cb5df3dc8deaffected
LinuxLinux0 < 6.12.109affected
LinuxLinux0 < 6.18.50affected
LinuxLinux0 < 7.2.4affected
LinuxLinux6.12.109 <= 6.12.*unaffected
LinuxLinux6.18.50 <= 6.18.*unaffected
LinuxLinux7.2.4 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References