Microsoft Windows Message Queueing Double Free Local Privilege Escalation Vulnerability
Vulnerability Details
This vulnerability allows local attackers to escalate privileges on affected installations of Microsoft Windows that run Message Queueing. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
The specific flaw exists within the mqac.sys driver. The issue results from the lack of validating the existence of an object prior to performing further free operations on the object. An attacker may be able to leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the kernel.
Additional Details
Microsoft has issued an update to correct this vulnerability. More details can be found at:
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33838
Disclosure Timeline
- 2026-01-08 - Vulnerability reported to vendor
- 2026-05-12 - Coordinated public release of advisory
- 2026-05-12 - Advisory Updated
Credit
Anonymous
