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.
- CVSS
- 6.8Mediumscored by the publisher (CNA)
- Exploited in the wild
- Not knownUnvetted proof-of-concept code on GitHub; not in CISA KEV
- EPSS
- 1.9%chance of exploitation in the next 30 daystop 21% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 20 May 2026analysed here 12 Nov 2026
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Microsoft Windows 11 Version 24H2 | >= 10.0.26100.0 and < 10.0.26100.8655Vendor says fixed in: not stated | |
| Microsoft Windows 11 Version 25H2 | >= 10.0.26200.0 and < 10.0.26200.8655Vendor says fixed in: not stated | |
| Microsoft Windows 11 version 26H1 | >= 10.0.28000.0 and < 10.0.28000.2269Vendor says fixed in: not stated | |
| Microsoft Windows Server 2025 | >= 10.0.26100.0 and < 10.0.26100.32995Vendor says fixed in: not stated | |
| Microsoft Windows Server 2025 (Server Core installation) | >= 10.0.26100.0 and < 10.0.26100.32995Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- microsoft:windows_11_24h2
- microsoft:windows_11_25h2
- microsoft:windows_11_26h1
- microsoft:windows_server_2025
Fix and mitigation
WAF and other mitigations
Can a WAF block it? No. The attack needs physical access to the machine, so a WAF is not on its path.
Also consider: input validation · RASP
Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Not listed as of our last sync.
- Public exploit code
- Unvetted proof-of-concept code on GitHub: 12 GitHub proofs of concept
- CISA SSVC
- exploitation poc, automatable no, technical impact totalAssessed by CISA 20 May 2026 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
GitHub proofs of concept
- Desireeontrial76/yellowkey-bitlocker11 stars
- andrei-majer/bitlocker-hardening6 stars
- everest90909/YellowKey-WinRE-Remediation1 stars
- 0xBlackash/CVE-2026-455851 stars
and 8 more repositories
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
Timeline
- 20 May 2026First proof-of-concept repository on GitHub (unvetted)
- 20 May 2026CISA SSVC assessment: exploitation pocsame day later
- 20 May 2026Publishedsame day later
- 10 Aug 2026CVE record last updated83 days (about 3 months) later
- 12 Nov 2026Analysed by vulneraibility.com94 days (about 3 months) later
CVSS vector
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | PhysicalRequires physical contact with the hardware. | Requires physical contact with the hardware. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2026-45585 being exploited?
Not confirmed. CVE-2026-45585 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 1.9% probability of exploitation in the next 30 days.
How severe is CVE-2026-45585?
CVE-2026-45585 is rated Medium with a CVSS score of 6.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-45585?
Yes. A fix has been recorded for CVE-2026-45585. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-45585 affect?
CVE-2026-45585 affects microsoft:windows_11_24h2, microsoft:windows_11_25h2, microsoft:windows_11_26h1, microsoft:windows_server_2025. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
2 references in the CVE record, grouped by the tags the record gives them.
Patches (1)
- msrc.microsoft.com /update-guide/vulnerability/CVE-2026-45585
Exploits (1)
- github.com /Nightmare-Eclipse/YellowKey
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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