Bug 2532381 (CVE-2026-80928)

Summary: CVE-2026-80928 kernel: smack: fix cred UAF in smack_file_send_sigiotask()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's SMACK (Simplified Mandatory Access Control Kernel) security module. Incorrect handling of task credentials within the smack_file_send_sigiotask() function can lead to a Use-After-Free (UAF) vulnerability. A local attacker could exploit this flaw to potentially escalate their privileges or disclose sensitive information by manipulating the timing of credential access.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-11 22:39:51 UTC 
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.
Comment 1 Keith Grant 2026-09-14 13:11:44 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80928.mbox