CVE-2026-58280: Microsoft Security Advisory CVE-2026-58280 - .NET and Visual Studio Denial of Service Vulnerability

Microsoft is releasing this security advisory to provide information about a vulnerability in System.Security.Cryptography.Xml and System.Private.Xml. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

Signed XML fixes add input-depth and operation-count limits, prohibit DTD processing by default, validate entity references, bound encrypted-data candidate processing, and cap attributes and namespaces used by C14N transforms.