GHSA-2j8r-3c22-8565: Buffer Overflow
Microsoft Security Advisory CVE-2026-69522 – .NET and Visual Studio Remote Code Execution Vulnerability
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.DiaSymReader.Native. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
An out of bounds write can occur when processing PDB files.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/439
CVSS Details
- Version: 3.1 - Severity: High - Score: 8.8 - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness: CWE-122 (Heap-based Buffer Overflow)
Affected Platforms
- Platforms: Windows - 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
Supported .NET Framework versions listed in the Microsoft Security Update Guide are also affected. Install the September 2026 .NET Framework security update applicable to a project's Windows version.
<a name=".NET 11 RC1"></a>.NET 11 RC1 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.DiaSymReader.Native | >= 17.10.0-beta1.24272.1, <= 18.9.0-beta1.26405.1 | 18.9.0-beta1.26405.2
<a name=".NET 10"></a>.NET 10 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.DiaSymReader.Native | >= 17.12.0-beta1.24603.5, <= 18.9.0-beta1.26405.1 | 18.9.0-beta1.26405.2
<a name=".NET 9"></a>.NET 9 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.DiaSymReader.Native | >= 17.12.0-beta1.24603.5, <= 18.9.0-beta1.26405.1 | 18.9.0-beta1.26405.2
<a name=".NET 8"></a>.NET 8 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.DiaSymReader.Native | >= 17.12.0-beta1.24603.5, <= 18.9.0-beta1.26405.1 | 18.9.0-beta1.26405.2
Advisory FAQ
<a name="how-affected"></a>How do I know if I am affected?
If using a package listed in affected packages, a project is exposed to the vulnerability.
<a name="how-fix"></a>How do I fix the issue?
1. To fix the issue please install the latest version of .NET or Visual Studio. .NET Framework users must install the September 2026 security update applicable to their Windows version. 2. If a developer's application references Microsoft.DiaSymReader.Native, update the package reference to version 18.9.0-beta1.26405.2 or later.
Once users have installed the updated runtime, SDK, Visual Studio, or package, they should restart their apps for the update to take effect.
Other Information
Reporting Security Issues
If users 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.
Support
Users 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. Users can ask questions in the linked discussion issue.
Disclaimer
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.
External Links
CVE-2026-69522
Acknowledgements
41ae55e9310ff27fa6f26af4727e5590
Revisions
V1.0 (09/08/2026): Advisory published.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
nuget/Microsoft.DiaSymReader.Nativeto a version that resolves this vulnerability.Fixed in 18.9.0-beta1.26405.2 - Upgrade
Upgrade
Microsoft.DiaSymReader.Nativeto a version that resolves this vulnerability.Fixed in 18.9.0-beta1.26405.2 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch September 2026 .NET Framework security update - Operational
After installing the updated runtime, SDK, Visual Studio, or package for CVE-2026-69522, restart affected apps for the update to take effect.
Event History
Frequently Asked Questions
Which environments should be prioritized for review?
Windows environments on any architecture should be reviewed if they run a Microsoft .NET project using an affected Microsoft.DiaSymReader.Native package version. Supported .NET Framework versions identified by Microsoft are also affected.
What conditions does exploitation require?
The vulnerable component must process a PDB file. The CVSS vector indicates exploitation is network-reachable, requires no attacker privileges, and requires user interaction.
What should teams do if they use the affected package?
Update affected Microsoft .NET projects to remove the vulnerable package version, following the advisory’s affected-package guidance. For affected supported .NET Framework installations, install the September 2026 .NET Framework security update.
How can we determine whether an application is affected?
Check the application’s resolved NuGet dependencies for Microsoft.DiaSymReader.Native and compare the installed version with the affected versions in the advisory. Also identify Windows systems using supported .NET Framework versions covered by Microsoft’s security update guidance.