[ CVE-2026-21510 · Published 10 Feb 2026 ]
Microsoft Windows Shell Protection Mechanism Failure Vulnerability
Exploited · CISA KEV CVSS 8.8
EPSS 25%No fix listed yet
[ Why it matters ]Priority signals
- Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-02-10
- EPSS: 25% chance of exploitation in the next 30 days (higher than 98% of CVEs)
[ Description ]Official description
Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.
CISA: Microsoft Windows Shell contains a protection mechanism failure vulnerability that could allow an unauthorized attacker to bypass a security feature over a network.
[ Fixes ]Fixes and patches
CISA required action (US federal deadline 3 Mar 2026): Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.
[ References ]References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21510Vendor Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource