GHSA-g8r8-53c2-pm3f: Microsoft Security Advisory CVE-2026-47304 – .NET Security Feature Bypass Vulnerability

Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in .NET XML Encryption (System.Security.Cryptography.Xml). This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. A security feature bypass vulnerability exists in the XML encryption implementation (EncryptedXml) in .NET 8, .NET 9, and .NET 10. An attacker could exploit this vulnerability to bypass encryption protections and access encrypted data. Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/412. CVSS Details - Version: 3.1 - Severity: High - Score: 8.1 - Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Weakness: CWE-347 (Improper Verification of Cryptographic Signature) Affected Platforms - Platforms: All - Architectures: All <a name="affected-packages"></a>Affected Packages The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below <a name=".NET 10.0"></a>.NET 10.0 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- System.Security.Cryptography.Xml | >= 10.0.0, <= 10.0.9 | 10.0.10 <a name=".NET 9.0"></a>.NET 9.0 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- System.Security.Cryptography.Xml | >= 9.0.0, <= 9.0.17 | 9.0.18 <a name=".NET 8.0"></a>.NET 8.0 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- System.Security.Cryptography.Xml | >= 8.0.0, <= 8.0.3 | 8.0.4 Advisory FAQ <a name="how-affected"></a>How do I know if I am affected? If using a package listed in affected packages, you're exposed to the vulnerability. <a name="how-fix"></a>How do I fix the issue? To update the System.Security.Cryptography.Xml NuGet package, use one of the following methods: NuGet Package