CVE-2026-70162: Microsoft Security Advisory CVE-2026-70162 - .NET Denial of Service Vulnerability

October 13, 2026 (updated October 19, 2026)

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

On Windows, EnvelopedCms.Decode can perform quadratic work while processing attacker-supplied CMS or PKCS#7 attributes, causing pre-authentication CPU exhaustion.

References

github.com/advisories/GHSA-2fmv-rv2c-59x7
github.com/dotnet/announcements/issues/454
github.com/dotnet/runtime/issues/135699
github.com/dotnet/runtime/security/advisories/GHSA-2fmv-rv2c-59x7
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70162
nvd.nist.gov/vuln/detail/CVE-2026-70162

Code Behaviors & Features

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