CVE-2025-55228: Microsoft Windows 10 Version 21H2 · Race Condition
Affects Microsoft Windows 10 Version 21H2Source CVE Database V5
Not known to be exploited · CVSS 7.8 High.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:CExploitation evidence
Disclosed: evidence found.
CVE published 9 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Windows 10 Version 21H2 | Affected
| Fixed in– |
AI-suggested
Until official patches are released, organizations should implement strict local access controls to limit the number of users with local login capabilities on affected systems. Employ application whitelisting and endpoint detection and response (EDR) tools to monitor for suspicious behavior indicative of race condition exploitation. Use virtualization or sandboxing to isolate critical applications and reduce attack surface. Regularly audit and restrict user privileges to the minimum necessary. Once Microsoft releases patches, prioritize their deployment across all affected Windows 10 Version 21H2 systems. Additionally, educate users and administrators about the risks of local privilege escalation vulnerabilities and encourage prompt reporting of unusual system behavior. Consider network segmentation to limit lateral movement from compromised endpoints. Maintain up-to-date backups to recover from potential attacks that impact system availability or integrity.
Description
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Win32K - GRFX allows an authorized attacker to execute code locally.