CVE-2025-53139: Microsoft Windows 10 Version 21H2 · Cleartext Transmission
Affects Microsoft Windows 10 Version 21H2Source CVE Database V5
Not known to be exploited · CVSS 7.7 High.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:CExploitation evidence
Disclosed: evidence found.
CVE published 14 Oct 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
Organizations should monitor Microsoft security advisories closely and apply patches promptly once released. Until a patch is available, restrict local access to systems running Windows 10 Version 21H2, especially those using Windows Hello. Implement strict access controls and network segmentation to limit exposure to potential local attackers. Employ endpoint detection and response (EDR) solutions to identify suspicious local activities indicative of exploitation attempts. Consider disabling Windows Hello temporarily in high-risk environments if feasible. Educate users about the risks of local access and enforce policies to prevent unauthorized physical or remote local access. Additionally, auditing authentication logs for anomalies can help detect exploitation attempts early. Finally, review and enhance internal security policies to minimize insider threat risks and ensure secure handling of authentication credentials.
Description
Cleartext transmission of sensitive information in Windows Hello allows an unauthorized attacker to bypass a security feature locally.