Microsoft: >> Windows 11 26h1 >> 10.0.28000.2525 Security Vulnerabilities
Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code locally.
CVSS Score
7.8
EPSS Score
0.009
Published
2026-07-14
Improper encoding or escaping of output in .NET allows an authorized attacker to perform spoofing over a network.
CVSS Score
6.5
EPSS Score
0.005
Published
2026-07-14
Improper verification of cryptographic signature in .NET allows an unauthorized attacker to bypass a security feature over a network.
CVSS Score
8.1
EPSS Score
0.002
Published
2026-07-14
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 Score
6.8
EPSS Score
0.014
Published
2026-05-20