February 10, 2026 · Applied Cybernetics Group
CVE-2026-21510 Microsoft Windows
Microsoft Windows Shell Protection Mechanism Failure Vulnerability
- Added to KEV
2026-02-10- Federal due date
2026-03-03- Vendor
- Microsoft
- Product
- Windows
- EPSS
- 99.2th percentile (score 0.612, as of
2026-11-06) - NVD CVSS v3.1
- 8.8 (HIGH)
- Ransomware use
- Unknown
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2026-21510
CISA short description
Microsoft Windows Shell contains a protection mechanism failure vulnerability that could allow an unauthorized attacker to bypass a security feature over a network.
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
NVD description
Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.