Microsoft has disclosed a new high-severity security flaw affecting multiple versions of Windows 10, Windows 11, and Windows Server. Tracked as CVE-2025-55224, this vulnerability resides in the Win32K GRFX component and could allow a local attacker to escalate privileges and run arbitrary code on the system.
If left unpatched, CVE-2025-55224 could open the door to serious security risks, especially in enterprise or virtualized environments.
What is CVE-2025-55224?
CVE-2025-55224 is classified as a race condition vulnerability (CWE-362) combined with potential use-after-free issues (CWE-416). These flaws occur when multiple processes compete for shared system resources without proper synchronization, leading to exploitable timing errors.
In practical terms, a low-privilege attacker logged into a vulnerable Windows system could trigger the flaw to gain elevated permissions—even achieving full system-level access.
Severity & CVSS Score
- CVSS 3.1 Base Score: 7.8 (High)
- Impact: Local privilege escalation and arbitrary code execution
- Attack Vector: Local (requires some initial access)
- User Interaction: None required
While the attack requires local access, the potential to move from a basic account to full administrative control makes this a serious escalation risk.
Affected Windows Versions
According to Microsoft advisories, CVE-2025-55224 affects the following systems prior to recent updates:
- Windows 10 (1809, 21H2, 22H2) – builds lower than patched versions (e.g., 19044.6332, 19045.6332)
- Windows 11 (22H2, 23H2, 24H2) – builds lower than 22621.5909, 22631.5909, or 26100.6508
- Windows Server 2019, 2022, and 2025 – various builds before September 2025 updates
If your build number is below these patched levels, your system remains vulnerable.
Why This Vulnerability Matters
- Privilege Escalation: Attackers can move from low-privileged accounts to system-level execution.
- Enterprise Risk: In environments where many users have local access, the chance of abuse is higher.
- Virtualization Impact: Hyper-V hosts could be compromised, impacting all guest virtual machines.
- Complete System Compromise: Successful exploitation can affect confidentiality, integrity, and availability of data.
How to Protect Your Systems
- Apply Microsoft Patches Immediately
CVE-2025-55224 has been fixed in the September 2025 Patch Tuesday updates. Updating is the most reliable protection. - Verify Build Versions
Check your Windows build (winvercommand) and ensure it is at or above the patched level. - Enforce Least Privilege
Reduce unnecessary local accounts and restrict access wherever possible. - Monitor Activity
Watch for unusual behavior from low-privilege accounts attempting unauthorized actions. - Harden Virtualized Environments
Hyper-V and server administrators should patch quickly, as host compromise can cascade across virtual machines.
Final Thoughts
CVE-2025-55224 is a high-risk Windows vulnerability that may not spread remotely, but its ability to grant attackers full system control makes it extremely dangerous. Organizations should treat this as a priority patching event.
Staying ahead of threats like this means regular patching, strict access controls, and proactive monitoring. If you manage Windows infrastructure, take action now to ensure your systems are safe.
