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Vulnerabilities

Security research · CVE-2026-62848

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

Published Nov 3, 2026 · catalog updated Nov 3, 2026 · Metalama: Unsafe deserialization over

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-62848. EPSS is 0.19%. Act only if a listed version of Metalama: Unsafe deserialization over is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Metalama: Unsafe deserialization over).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.19%
Remediation
Version ranges on file
Affected products
nuget Metalama.Framework · nuget metalama.framework

## Summary Metalama uses a local named-pipe channel to communicate between its Visual Studio processes — the Visual Studio UI process ( ), 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 (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: , derived from the public package version and a locally-enumerable process id. This channel is used by the Visual Studio integration only (Windows named pipes); it is not used for command-line / MSBuild builds. ## Mechanisms **JSON era — Metalama 2023.0 through 2026.0.x (Newtonsoft.Json).** The pipe formatter enabled polymorphic type embedding: The accompanying (added later for multi-version assembly support) only **remapped assembly names**; its resolved **any** type name from the wire ( ) with **no type allow-list**. is the canonical unsafe-deserialization setting and has publicly available gadget chains (e.g. ysoserial.net), so this era is at least as exploitable as the later one. (Introduced by commit , first shipped in .) **MessagePack era — Metalama 2026.1.0 through 2026.1.18.** The 2026.1 line migrated the pipe serialization to MessagePack (PR #1299, commit , 2026-01-29), using **typeless** MessagePack ( ), which likewise embeds CLR type names on the wire and instantiates arbitrary types on receipt — again with no allow-list. Both mechanisms share the same channel, the same predictable pipe name, the same impact, and the same access preconditions. ## Impact Potential arbitrary code execution inside the Visual S

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • nuget Metalama.Framework< 2025.1.18
  • nuget Metalama.Framework>= 2026.0.1-preview, < 2026.0.25
  • nuget Metalama.Framework>= 2026.1.0-preview, < 2026.1.19
  • nuget metalama.frameworkversion unspecified

How to fix CVE-2026-62848

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-62848. EPSS is 0.19%. Act only if a listed version of Metalama: Unsafe deserialization over is installed.

Which versions are affected?

Compare what you have installed with Metalama.Framework < 2025.1.18; Metalama.Framework >= 2026.0.1-preview, < 2026.0.25; Metalama.Framework >= 2026.1.0-preview, < 2026.1.19. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-502: Deserialization of Untrusted Data; CWE-913: Improper Control of Dynamically-Managed Code Resources. EPSS 0.19%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 3, 2026 · GitHub Advisory Database

    Detected

    ## Summary Metalama uses a local named-pipe channel to communicate between its Visual Studio processes — the Visual Studio UI process ( ), 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

  2. Nov 3, 2026 · GitHub Advisory Database

    Updated

    ## Summary Metalama uses a local named-pipe channel to communicate between its Visual Studio processes — the Visual Studio UI process ( ), 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

Sources

  • CVE.orgVulnerability recordCVE-2026-62848

    Official CVE identifier

    cve.org
  • GitHub Advisory DatabasePackage advisoryGHSA-h26j-4vp7-x9w2

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

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-62848

    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 instantiat

    advisories.gitlab.com

References

Freshness

Last verified in this catalog Nov 4, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • GitLab Advisory DatabaseNov 7, 2026
  • GitHub Advisory DatabaseNov 7, 2026
  • CVE.orgNov 4, 2026