CVE-2026-21510 — Microsoft Windows Shell Protection Mechanism Failure Vulnerability
Overview
Microsoft Windows Shell contains a protection mechanism failure vulnerability that could allow an unauthorized attacker to bypass a security feature over a network.
Vulnerability details
- CVE ID
- CVE-2026-21510
- Vulnerability
- Microsoft Windows Shell Protection Mechanism Failure Vulnerability
- Vendor
- Microsoft
- Affected products
- Microsoft: Windows
- Severity
- HIGH
- Exploitation status
- Actively exploited in the wild (CISA KEV)
- EPSS score
- 25.8% probability of exploitation in 30 days · 98th percentile
- Published
- 2026-02-10
Remediation guidance
CVE-2026-21510 is in CISA's Known Exploited Vulnerabilities (KEV) catalog — U.S. federal civilian agencies are required to remediate it under Binding Operational Directive 22-01. Treat it as a priority for every environment.
Apply the vendor's official security update for Microsoft the affected product as soon as possible. Where a patch is unavailable, apply vendor mitigations or isolate/segment exposed systems.
FIRST EPSS estimates a 25.8% probability that CVE-2026-21510 will be exploited within the next 30 days (98th percentile of all CVEs) — useful for risk-based patch sequencing.
Hunt for indicators of compromise tied to this vulnerability and confirm logging/EDR coverage on affected assets.
Authoritative references
Remediate CVE-2026-21510 — and stay ahead of the next one
CVE-2026-21510 is listed in the CISA KEV catalog as actively exploited — treat remediation as urgent. Scan your domain free to see whether CVE-2026-21510 and other Microsoft issues affect you and get a prioritized remediation report (full report from ₹999) — or stream the full feed of 1,600+ actively-exploited CVEs straight into your SOC.
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