CVE-2025-21371: Microsoft Windows 10 Version 1507 · Heap-based Buffer Overflow
Affects Microsoft Windows 10 Version 1507Source CVE Database V5
Not known to be exploited · CVSS 8.8 High.
Data as of 26 Oct 2026, 09:15 UTC
- EPSS
- 2.4% chance of exploitation in 30 days – higher than 84% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CExploitation evidence
Disclosed: evidence found.
CVE published 11 Feb 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 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Windows 10 Version 1507 | Affected
| Fixed in– |
AI-suggested
Organizations should immediately assess their Windows 10 deployments to identify systems running Version 1507 (build 10.0.10240.0). Network-level controls such as firewall rules should block inbound traffic to ports and protocols used by the Telephony Service to reduce exposure. User education to avoid interacting with suspicious links or files can reduce the risk of exploitation requiring user interaction. Monitoring and logging telephony service activity for anomalies can help detect exploitation attempts. Organizations should plan to upgrade affected systems to supported Windows versions with security updates. Once Microsoft releases a patch, it should be applied promptly. Additionally, deploying endpoint detection and response (EDR) solutions can help identify and contain exploitation attempts.
Description
Windows Telephony Service Remote Code Execution Vulnerability
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21371 (opens in a new tab)
- vicarius.io/vsociety/posts/windows-telephony-service-remote-code-execution-vulnerability-detection-script (opens in a new tab)
- vicarius.io/vsociety/posts/windows-telephony-service-remote-code-execution-vulnerability-mitigation-script (opens in a new tab)