Linux Kernel Vulnerability in Performance Monitoring Tools

CVE-2026-89791

What is CVE-2026-89791?

A vulnerability in the Linux kernel related to performance monitoring tools has been identified, where a race condition can lead to a use-after-free scenario. This occurs in the 'perf' subsystem during the mmap() operation, allowing an unprivileged user to escalate privileges to root. The issue arises when multiple threads access the same performance monitoring event without proper synchronization locks, potentially freeing memory that another thread still uses. The vulnerability has been addressed by reordering reference count updates to ensure proper serialization, preventing the misuse of memory accesses during concurrent operations.

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