Metalama: Unsafe deserialization over Metalama's Visual Studio inter-process named pipe enables local code execution

Exploitation

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

CVSS

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

EPSS

• CVE-2026-62848: 0.19% estimated exploitation activity in the next 30 days; percentile 8.31 (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.

Summary Metalama uses a local named-pipe channel to communicate between its Visual Studio processes — the Visual Studio UI process (`devenv`), the out-of-process Roslyn code-analysis process, and the CodeLens process. This channel deserialized messages from the pipe without restricting which CLR types could be instantiated. A local process able to write to the pipe can send a crafted message that instantiates arbitrary .NET types — a deserialization primitive in the same class as `BinaryFormatter` (CWE-502), and a well-known gadget-chain code-execution vector. The flaw is present, via two successive serializers, in every Metalama release from the first public version (2023.0) up to and including 2026.1.18, and is fixed in 2026.1.19. The pipe name is predictable: `Metalama_{role}_{processId}_{hash(PackageVersion)}`, derived from the public package version and a locally-enumerable process id. This channel is used by the Visual Studio integration only (Windows named…

Published by the source

3 Nov 2026, 16:37 UTC

Last modified by the source

3 Nov 2026, 16:45 UTC

Source last checked

4 Nov 2026, 06:40 UTC

1. Revision 2 · amended · 4 Nov 2026

   Amended from osv record GHSA-h26j-4vp7-x9w2

2. Revision 1 · created · 3 Nov 2026

   Published from ghsa record GHSA-h26j-4vp7-x9w2

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# Patch Next advisory brief: CVE-2026-62848

Advisory: Metalama: Unsafe deserialization over Metalama's Visual Studio inter-process named pipe enables local code execution
IDs: CVE-2026-62848, GHSA-h26j-4vp7-x9w2
Record: https://patchnext.com/advisories/cve-2026-62848 (revision 2, source checked 4 Nov 2026, 06:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: metalama.framework 2026.1.19, 2026.0.25, 2025.1.18. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet metalama.framework: affected >= 2026.1.0-preview, < 2026.1.19; < 2025.1.18; >= 2026.0.1-preview, < 2026.0.25; fixed in 2026.0.25, 2026.1.19, 2025.1.18

## Suggested inspection (read-only)
- NuGet metalama.framework: 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 metalama.framework.
- 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://github.com/advisories/GHSA-h26j-4vp7-x9w2 (GitHub-reviewed advisory GHSA-h26j-4vp7-x9w2 lists affected ranges: NuGet metalama.framework >=2026.1.0-preview =0 =2026.0.1-preview <2026.0.25)
- Verified: https://osv.dev/vulnerability/GHSA-h26j-4vp7-x9w2 (OSV record GHSA-h26j-4vp7-x9w2 lists affected ranges: NuGet metalama.framework >=2026.1.0-preview =0 =2026.0.1-preview <2026.0.25 (fixed))

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