A high-severity Use After Free vulnerability in multiple Arm GPU userspace drivers allows local attackers to gain unauthorized access to memory, posing a risk of system compromise.

This vulnerability is a Use After Free (CWE-416) flaw occurring within the GPU userspace drivers. A local, non-privileged user process can trigger this condition by performing standard GPU operations, such as those initiated through WebGL or WebGPU, to interact with memory that has already been freed.

The vulnerability carries a CVSS score of 7.8, reflecting its potential for complete impact on confidentiality, integrity, and availability. Successful exploitation allows a local user to escalate privileges or execute arbitrary code within the context of the GPU driver, which often operates with high system privileges. This poses a significant threat to data privacy and system stability, particularly in multi-user environments or systems running untrusted browser-based content.

Immediate Action: Update affected Valhall and 5th Gen GPU drivers to version r56p0 or later. For Bifrost driver users, monitor the Arm support portal for the release of a corresponding security patch, as no fix is currently listed for that specific product line.

Proactive Monitoring: Monitor system logs for unusual crashes related to GPU processes or abnormal memory access patterns that might indicate exploitation attempts.

Compensating Controls: Restrict access to applications or browser features that utilize WebGL or WebGPU if the system is at high risk and cannot be immediately updated.

Public Exploit Available: Unknown.

Given the severity of this vulnerability, administrators must prioritize the update of Valhall and 5th Gen drivers as soon as the r56p0 version becomes available through their hardware or OS vendors. For the Bifrost series, continue to monitor vendor documentation for a fixed version release. Failure to patch these drivers leaves systems vulnerable to local privilege escalation and arbitrary code execution by any user with local access.