Executive brief
A security vulnerability has been identified in the .NET component responsible for processing encrypted XML data. An attacker can exploit this flaw to cause a denial of service, potentially crashing applications or making them unresponsive. This impacts the availability of services that rely on .NET for secure data exchange. Developers should update their software to the latest patched versions of the affected library to maintain service stability.
Technical details
A denial of service vulnerability exists in the EncryptedXml implementation within the System.Security.Cryptography.Xml package for .NET 8, 9, and 10. The root cause is a resource exhaustion issue (CWE-770) where the library fails to properly limit or throttle resource allocation during the decryption of specially crafted XML payloads. An unauthenticated remote attacker can exploit this by sending malicious XML data, leading to uncontrolled resource consumption and application unavailability. Patches are available in versions 8.0.29, 9.0.18, and 10.0.10.
Affected products
- Microsoft System.Security.Cryptography.Xml >= 8.0.0, <= 8.0.28
- Microsoft System.Security.Cryptography.Xml >= 9.0.0, <= 9.0.17
- Microsoft System.Security.Cryptography.Xml >= 10.0.0, <= 10.0.9
Timeline
- 2026-07-14: disclosed: Advisory published by Microsoft
- 2026-07-20: advisory: GitHub Advisory published/reviewed
References
- https://github.com/dotnet/runtime/security/advisories/GHSA-8q5v-6pqq-x66h
- https://github.com/dotnet/announcements/issues/414
- https://github.com/dotnet/runtime/issues/130711
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50525
- https://api.github.com/repos/dotnet/runtime/security-advisories/GHSA-8q5v-6pqq-x66h