In the Linux kernel, the following vulnerability has been resolved: rtmutex: Use waiter::task instead of current in remove_waiter() remove_waiter()...
Description
In the Linux kernel, the following vulnerability has been resolved: rtmutex: Use waiter::task instead of current in remove_waiter() remove_waiter() is used by the slowlock paths, but it is also used for proxy-lock rollback in rt_mutex_start_proxy_lock() when invoked from futex_requeue()
AI Analyst Comment
Remediation
Apply vendor security updates immediately. Monitor for exploitation attempts and review access logs.
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VENDOR: Linux
PRODUCT: kernel
AFFECTED_VERSIONS: Introduced in 2.6.39; fixed in stable 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4, and mainline 7.1 (distro kernels backport; check your distribution's advisory)
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Description Summary:
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 Details
CVE-ID: CVE-2026-43499
Affected Software: Linux kernel
Affected Versions: See vendor advisory
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 Plan
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 Notes: As of June 1, 2026, there is no public information indicating active exploitation of this vulnerability. However, due to the nature of the flaw, the potential for exploitation is high.
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.