Linux Kernel SELinux Buffer Handling Vulnerability

CVE-2026-98413

What is CVE-2026-98413?

A vulnerability in the Linux kernel's SELinux implementation raises concerns over access control mechanisms. The issue lies in the avc_has_perm_noaudit() function, which is supposed to return a defined access decision in the provided buffer. However, if the requested permission set is empty, the function prematurely returns while leaving the buffer uninitialized. This could compromise security, as all callers that depend on this function might use the uninitialized stack variable, potentially leading to unpredictable behavior. The fix implements a mechanism to fill the buffer with a deny-all, audit-all access decision, ensuring every caller receives a well-defined value, thereby maintaining the integrity of access decisions in the SELinux framework.

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