Linux Kernel Vulnerability Affecting POSIX Timers Cleanup Process

CVE-2026-98260

What is CVE-2026-98260?

CVE-2026-98260 is a significant vulnerability in the Linux kernel related to the handling of POSIX timers within the cleanup process during the execution of threads. Specifically, this vulnerability pertains to a situation where a non-leader thread executes a new program without correctly cleaning up its CPU timers after the thread’s identity changes, potentially leading to inconsistent states within the timer management system. The flaw arises from the incorrect deallocation of a timer node, which remains queued even after the associated thread reference is altered. If a failure occurs after certain operations, this can lead to a situation where a freed timer is still accessed, resulting in a use-after-free error. This vulnerability poses a considerable risk to organizations utilizing affected versions of the Linux kernel, as it can lead to unstable system performance and potential exploitation by malicious actors.

Potential impact of CVE-2026-98260

1. System Instability: The vulnerability may lead to the loss of timer management integrity, causing processes to behave unpredictably and contributing to overall system crashes or hangs due to the mishandling of thread states.

2. Exploitation Risk: If successfully exploited, this vulnerability could provide an attacker with the ability to execute arbitrary code or elevate privileges within an affected system, potentially leading to unauthorized access and control of sensitive data or critical infrastructure.

3. Increased Attack Surface: As the vulnerability allows for possible exploitation, it may expose organizations to further attacks, particularly from ransomware groups that actively seek out weaknesses in widely used software to deploy malicious payloads and encrypt valuable data for ransom.

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