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CVE-2026-23248
HIGH · CVSS 7.8
EPSS exploitation probability: 0%
Published 2026-03-18T11:16:16.863 · Last modified 2026-06-17T10:21:11.000

Summary

In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix refcount bug and potential UAF in perf_mmap Syzkaller reported a refcount_t: addition on 0; use-after-free warning in perf_mmap. The issue is caused by a race condition between a failing mmap() setup and a concurrent mmap() on a dependent event (e.g., using output redirection). In perf_mmap(), the ring_buffer (rb) is allocated and assigned to event->rb with the mmap_mutex held. The mutex is then released to perform map_range(). If map_range() fails, perf_mmap_close() is called to clean up. However, since the mutex was dropped, another thread attaching to this event (via inherited events or output redirection) can acquire the mutex, observe the valid event->rb pointer, and attempt to increment its refere

Affected products

linux — linux_kernel

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References

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