CVE-2026-21510 on CISA KEV

Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.

01What CISA says about this vulnerability

Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.

02Required action — verbatim from CISA

- CISA KEV: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

03Notes & references

No additional references available in the KB record.

04SARA's analyst layer — why this matters

This vulnerability is currently on the CISA KEV list, which CISA only adds CVEs to when there is reliable evidence of active exploitation in the wild. For federal civilian agencies, BOD 22-01 requires remediation by the due date above. For everyone else, KEV is the strongest "patch immediately" signal you can get from public threat intel.

05Affected products (summary)

No structured affected-product list available — see references below for vendor advisories.

06Detection

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