CVE-2026-43499

Linux · kernel

A use-after-free vulnerability in the Linux kernel's rtmutex component during proxy-lock rollback can lead to privilege escalation.

Executive summary

A high-severity use-after-free vulnerability in the Linux kernel's real-time mutex subsystem could allow a local attacker to gain elevated privileges.

Vulnerability

During a proxy-lock rollback in rt_mutex_start_proxy_lock(), the kernel incorrectly handles task pointers. This results in a use-after-free condition where a reference to a task is used after it has been improperly managed.

Business impact

The CVSS score of 7.8 underscores the severity of this vulnerability. By exploiting this flaw, a local attacker could potentially achieve privilege escalation, compromising the entire system.

Remediation

Immediate Action: Update the Linux kernel to a patched version that correctly utilizes waiter::task in remove_waiter().

Proactive Monitoring: Monitor for suspicious local processes attempting to interact with futex or real-time mutex operations.

Compensating Controls: Restrict access to local system resources and implement kernel hardening measures to mitigate potential privilege escalation attempts.

Exploitation status

Public Exploit Available: false

Analyst recommendation

Given the potential for privilege escalation, this patch is of high importance. Administrators must ensure that the kernel is updated to a non-vulnerable version as soon as possible.