The vulnerability CVE-2026-45585 (CVSS 6.8) is a command injection flaw in the Windows BitLocker recovery environment, known as 'YellowKey', allowing local attackers to bypass security features and access encrypted data. It affects Windows 11 versions 24H2, 25H2, 26H1, and Windows Server 2025. Microsoft is developing a security update; until its release, administrators should implement the temporary mitigating measures referenced in the NCSC advisory.
Beveiligingsadviezen Download Beveilingsadvies; NCSC-2026-0165 [1.0.0] Beveiligingsadvies NCSC-2026-0165 [1.0.0] Publicatie 20-05-2026 08:21 (Europe/Amsterdam) Prioriteit Normaal Betreft Kwetsbaarheid aangetroffen in Microsoft Windows Kenmerken Improper Neutralization of Special Elements used in a Command ('Command Injection') Omschrijving Microsoft heeft maatregelen gepubliceerd voor een kwetsbaarheid in Windows besturingssystemen waarmee lokale kwaadwillenden toegang kunnen krijgen tot data die via BitLocker is versleuteld. De kwetsbaarheid betreft een security feature bypass in Windows, bekend als 'YellowKey'. Er is een proof of concept beschikbaar die aantoont hoe de kwetsbaarheid kan worden misbruikt. De kwetsbaarheid zit niet in de encryptie zelf, maar in de herstelomgeving die BitLocker omringt. Oplossingen Microsoft is bezig met het uitbrengen van een security update om de kwetsbaarheid volledig te verhelpen. Tot die tijd zijn er mitigerende maatregelen beschikbaar die als tijdelijke maatregel kunnen worden toegepast. Zie bijgevoegde referenties voor meer informatie. Referenties https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45585 CVE's CVE-2026-45585 - CVSS (v3) 6.8 Producten Microsoft Windows 11 Version 24H2 Windows 11 Version 24H2 for x64-based Systems Windows 11 Version 25H2 Windows 11 Version 25H2 for x64-based Systems Windows 11 version 26H1 Windows 11 version 26H1 for x64-based Systems Windows Server 2025 Windows Server 2025 (Server Core installation) Disclaimer The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this page to enhance access to its information and security advisories. The use of this security advisory is subject to the following terms and conditions: NCSC-NL makes every reasonable effort to ensure that the content of this page is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or continuous keeping up-to-date. The information contained in this security advisory is intended solely for the purpose of providing general information to professional users. No rights can be derived from the information provided therein. NCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of this security advisory. This includes damage resulting from the inaccuracy of incompleteness of the information contained in the advisory. This security advisory is subject to Dutch law. All disputes related to or arising from the use of this advisory will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings.