Microsoft Windows Shell Protection Mechanism Failure Vulnerability
Microsoft — Windows 10 Version 1607
Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.
8.8
25.8%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
- Published
- Feb 10, 2026
- Modified
- Aug 19, 2026
- Added to KEV
- Feb 10, 2026
- Federal patch due
- Mar 3, 2026
CISA 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.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2026-21510, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit — cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2026-21510 were found at last check. Absence here is not proof no exploit exists — see the references below for vendor advisories and write-ups.
References
Frequently asked questions
What is CVE-2026-21510?
Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.
How severe is CVE-2026-21510?
CVE-2026-21510 has a CVSS base score of 8.8 out of 10 (CVSS 3.1).
Is CVE-2026-21510 actively exploited in the wild?
Yes. CVE-2026-21510 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Feb 10, 2026, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2026-21510?
25.8% - meaning FIRST.org's EPSS model estimates a 25.8% probability this vulnerability will be exploited in the wild within 30 days (98% percentile among all scored CVEs).
What type of vulnerability is CVE-2026-21510?
CVE-2026-21510 is classified under CWE-693 (CWE-693: Protection Mechanism Failure).
Cross-checked against
Impactr finds and proves whether CVE-2026-21510 — or flaws like it — are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.