# CVE-2026-45585

Microsoft is aware of a security feature bypass vulnerability in Windows publicly referred to as "YellowKey". The proof of concept for this vulnerability has been made public violating coordinated vulnerability best practices. We are issuing this CVE to provide mitigation guidance that can be implemented to protect against this vulnerability until the security update is made available. Mitigation FAQs Should I leverage the temporary mitigation? Microsoft recommends that you consider implementing these mitigations if you are concerned your devices and data are at risk of being compromised or stolen. For example, if your organization’s employees take their work devices home or on business travel. What impact to service availability/management could be caused by implementing the mitigations? Implementing these mitigations will not impact service availability or management operations. Do customers need to revert the changes made to mitigate the vulnerability once the security update to protect against this vulnerability is available? No. The security update will maintain the mitigation's behavior once the security update is installed. I am using TPM+PIN, am I at risk of this vulnerability being exploited No, if you are using TPM+PIN the vulnerability is not exploitable.

- Page: https://www.vulneraibility.com/cve/CVE-2026-45585
- CVSS: 6.8
- Known exploited: not in CISA KEV as of our last sync
- EPSS: 1.89% (percentile 79.9)
- Unvetted proof-of-concept code on GitHub: 12 GitHub proofs of concept (first 2026-05-20)
- CISA SSVC: exploitation poc, automatable no, technical impact total (assessed 2026-05-20)
- Weakness: CWE-77
- Published: 2026-05-20

## Affected versions

- Microsoft Windows 11 Version 24H2: affected >= 10.0.26100.0 and < 10.0.26100.8655
- Microsoft Windows 11 Version 25H2: affected >= 10.0.26200.0 and < 10.0.26200.8655
- Microsoft Windows 11 version 26H1: affected >= 10.0.28000.0 and < 10.0.28000.2269
- Microsoft Windows Server 2025: affected >= 10.0.26100.0 and < 10.0.26100.32995
- Microsoft Windows Server 2025 (Server Core installation): affected >= 10.0.26100.0 and < 10.0.26100.32995

A version outside these ranges is not a statement that it is unaffected.

## References

- [patch] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45585
- [exploit] https://github.com/Nightmare-Eclipse/YellowKey

---
Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.