CVE-2026-23014 in Linux
Summary
by MITRE • 01/28/2026
In the Linux kernel, the following vulnerability has been resolved:
perf: Ensure swevent hrtimer is properly destroyed
With the change to hrtimer_try_to_cancel() in perf_swevent_cancel_hrtimer() it appears possible for the hrtimer to still be active by the time the event gets freed.
Make sure the event does a full hrtimer_cancel() on the free path by installing a perf_event::destroy handler.
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Analysis
by VulDB Data Team • 03/26/2026
The vulnerability identified as CVE-2026-23014 resides within the Linux kernel's performance monitoring subsystem, specifically affecting the handling of software event high-resolution timers. This issue manifests in the perf subsystem's swevent hrtimer management mechanism, where improper cleanup procedures can lead to resource leakage and potential system instability. The vulnerability stems from a race condition scenario during the destruction of performance monitoring events, where the hrtimer may remain active even after the event structure has been freed, creating a dangerous state that could be exploited by malicious actors.
The technical flaw occurs within the perf_swevent_cancel_hrtimer() function where the implementation relies on hrtimer_try_to_cancel() which does not guarantee that the high-resolution timer has completely stopped before proceeding with event cleanup. This function returns immediately if the timer is already running or has already been canceled, potentially leaving the timer in an inconsistent state. The root cause lies in the incomplete synchronization between timer cancellation and event destruction, allowing for a window where timer callbacks might still execute against freed memory structures, leading to memory corruption or undefined behavior.
The operational impact of this vulnerability extends beyond simple resource leakage, potentially enabling privilege escalation attacks or system crashes through controlled memory corruption. When performance monitoring events are destroyed without proper hrtimer cleanup, the kernel's memory management can become corrupted as timer callbacks attempt to access deallocated structures. This presents a significant risk to system stability and security, particularly in environments where performance monitoring is heavily utilized or where malicious actors might attempt to exploit the timing window for privilege escalation. The vulnerability affects systems running affected Linux kernel versions and can be triggered through normal performance monitoring operations.
Mitigation strategies for CVE-2026-23014 require immediate kernel updates to patched versions that implement proper hrtimer cancellation through the installation of a perf_event::destroy handler. This handler ensures that a full hrtimer_cancel() operation is performed during the event destruction path, eliminating the race condition that allows timers to remain active. System administrators should prioritize patching their kernel versions and monitor for any performance monitoring anomalies that might indicate the vulnerability's exploitation. Additionally, implementing proper kernel hardening measures such as stack canaries and kernel address space layout randomization can provide additional defense-in-depth protection against potential exploitation attempts.
This vulnerability aligns with CWE-362, which addresses concurrent execution using improper synchronization, and maps to ATT&CK technique T1059.001 for privilege escalation through kernel exploits. The fix implements proper resource management practices that align with secure coding guidelines for kernel development, ensuring that all allocated resources are properly freed and synchronized during the destruction of kernel objects. The solution demonstrates the importance of proper synchronization mechanisms in kernel-level programming where race conditions can lead to severe security implications.