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Linux kernel perf __perf_event_overflow() race condition

IdentifiersCVE-2026-23271CWE-362· Concurrent Execution using Shared…

CVE-2026-23271 is a race condition in the Linux kernel perf subsystem. According to the provided description, __perf_event_overflow() was not guaranteed to run with IRQs disabled on all possible call paths; in particular, software events could invoke it with only preemption disabled. This created a race window against perf_remove_from_context(), perf_event_exit_event(), and related teardown paths, which could free objects that the overflow handling path still expected to be valid, including associated BPF program state. The issue was resolved by ensuring __perf_event_overflow() executes with IRQs disabled for all relevant call chains.

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Impact, mitigation & remediation

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Impact

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Successful exploitation of this race condition could lead to a use-after-free style memory safety failure in kernel context during perf event overflow handling. Depending on timing and reachable freed objects, impact could include kernel crashes or other undefined behavior. Because the affected code path references freed kernel objects such as BPF program state, the vulnerability may also present a path toward more serious kernel memory corruption outcomes, but the provided content does not establish a specific demonstrated privilege-escalation or code-execution result.

Mitigation

If you can’t patch tonight, do this now.

Until patched kernels can be deployed, reduce exposure by restricting access to perf events and related profiling capabilities to trusted users only, and disable or tightly control unprivileged perf usage where supported by system policy. Minimizing access to perf/BPF-related functionality may reduce exploitability, but no complete mitigation is provided in the supplied content short of applying the kernel fix.

Remediation

Patch, then assume compromise.

Apply the upstream Linux kernel fix for CVE-2026-23271 that ensures __perf_event_overflow() runs with IRQs disabled across all possible call chains, including software event paths. Use a kernel release that contains the perf subsystem patch addressing the __perf_event_overflow() versus perf_remove_from_context()/perf_event_exit_event() race.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

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VendorProductType
LinuxLinux Kerneloperating_system

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