Microsoft Security Advisory CVE-2026-69439 – .NET and Visual Studio Elevation of Privilege Vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-69439: 0.82% estimated exploitation activity in the next 30 days; percentile 57.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Microsoft Security Advisory CVE-2026-69439 – .NET and Visual Studio Elevation of Privilege 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 parsing a Portable PDB file. Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/438 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"</aAffected Packages The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below <a name=".NET 11 RC1"</a.NET 11 RC1 Package name | Affected version |…

Published by the source

9 Sep 2026, 16:03 UTC

Last modified by the source

1 Oct 2026, 10:10 UTC

Source last checked

26 Oct 2026, 17:05 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-527h-q9f6-p7qx

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-527h-q9f6-p7qx

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# Patch Next advisory brief: CVE-2026-69439

Advisory: Microsoft Security Advisory CVE-2026-69439 – .NET and Visual Studio Elevation of Privilege Vulnerability
IDs: CVE-2026-69439, GHSA-527h-q9f6-p7qx
Record: https://patchnext.com/advisories/cve-2026-69439 (revision 2, source checked 26 Oct 2026, 17:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: microsoft.diasymreader.native 18.9.0-beta1.26405.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet microsoft.diasymreader.native: affected >= 17.10.0-beta1.24272.1, <= 18.9.0-beta1.26405.1; fixed in 18.9.0-beta1.26405.2

## Suggested inspection (read-only)
- NuGet microsoft.diasymreader.native: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on microsoft.diasymreader.native.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-527h-q9f6-p7qx (OSV record GHSA-527h-q9f6-p7qx lists affected ranges: NuGet microsoft.diasymreader.native >=17.10.0-beta1.24272.1 <18.9.0-beta1.26405.2 (fixed))
- Verified: https://github.com/advisories/GHSA-527h-q9f6-p7qx (GitHub-reviewed advisory GHSA-527h-q9f6-p7qx lists affected ranges: NuGet microsoft.diasymreader.native >=17.10.0-beta1.24272.1 <=18.9.0-beta1.26405.1)

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