Live › vulnerability › CVE-2026-96222
Go to dashboardSystem.Security.Cryptography.Xml accepts serialized certificate formats with attacker-controlled chain metadata in KeyInfoX509Data instead of requiring a plain X.509 certificate. The advisory says this contributes to certificate-forgery and token-spoofing paths, so an attacker may be able to get forged signed XML or tokens accepted.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 19:11 UTC, 5h before NVD. All times on this page are UTC.
| Product | Ecosystem | Affected | Fixed in |
|---|---|---|---|
| System.Security.Cryptography.Xml | nuget | >= 8.0.0, <= 8.0.4 | 8.0.5 |
| microsoft windows 10 1607 | vendor | < 10.0.14393.9612 | 10.0.14393.9612 |
| microsoft windows 10 1809 | vendor | < 10.0.17763.9376 | 10.0.17763.9376 |
| microsoft windows server 2012 | vendor | – | – |
| microsoft windows server 2012 | vendor | = r2 | – |
| microsoft windows server 2016 | vendor | < 10.0.14393.9612 | 10.0.14393.9612 |
| microsoft windows server 2019 | vendor | < 10.0.17763.9376 | 10.0.17763.9376 |
| microsoft windows server 2022 | vendor | < 10.0.20348.5761 | 10.0.20348.5761 |
| microsoft windows server 2025 | vendor | < 10.0.26100.33650 |
| 10.0.26100.33650 |
| microsoft .net | vendor | >= 8.0.0, < 8.0.5 | 8.0.5 |
| microsoft visual studio 2022 | vendor | >= 17.14.0, < 17.14.42 | 17.14.42 |
| microsoft visual studio 2026 | vendor | >= 18.10.0, < 18.10.4 | 18.10.4 |
| microsoft .net framework | vendor | = 4.8.1 | – |
| microsoft .net framework | vendor | = 4.8 | – |
| microsoft .net framework | vendor | = 4.6.2 | – |
| microsoft .net framework | vendor | = 4.7 | – |
| microsoft .net framework | vendor | = 4.7.1 | – |
| microsoft .net framework | vendor | = 4.7.2 | – |
| microsoft .net framework | vendor | = 3.5 | – |
dotnet list package --include-transitive | grep System.Security.Cryptography.Xml
grep -ri "System.Security.Cryptography.Xml" --include=*.csproj --include=packages.lock.json .
If the version is between 8.0.0 and 8.0.4 inclusive, the app is affected.
8.0.5 or later, or install the latest .NET patch releaseEach row is the first time that source carried this signal. The analyst’s rows are its own findings.
Microsoft is releasing this security advisory to provide information about a vulnerability in System.Security.Cryptography.Xml. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
KeyInfoX509Data can accept serialized certificate formats containing attacker-controlled chain metadata instead of requiring a plain X.509 certificate, contributing to certificate-forgery and token-spoofing paths.
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/474
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NThe vulnerability affects Microsoft .NET projects that use an affected package version listed below.
| Package name | Affected version | Patched version |
|---|---|---|
| System.Security.Cryptography.Xml | >= 8.0.0, <= 8.0.4 | 8.0.5 |
If using a package listed in affected packages, you're exposed to the vulnerability.
dotnet --info command.Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.
Additionally, if you've deployed self-contained applications targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.
If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.
Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.
You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.
The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
V1.0 (10/13/2026): Advisory published.
This page as .md · .json · in your agent: get_signal("CVE-2026-96222")
GitHub Advisory Database, CC-BY 4.0 · NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.