Metalama's Visual Studio inter-process named pipe allows unsafe deserialization that enables local code execution

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-62848
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-30 21:17:13 UTC
Updated2026-10-30 21:17:13 UTC
DescriptionMetalama is a Roslyn-based open-source patterns and architecture toolkit for C#. From 2023.0.101-rc until 2025.1.18, 2026.0.25 and 2026.1.19, the Windows Visual Studio integration deserializes local named-pipe messages without restricting which CLR types can be instantiated. The pipe connects `devenv`, the out-of-process Roslyn code-analysis process and the `CodeLens` process, and has the predictable name `Metalama_{role}_{processId}_{hash(PackageVersion)}`. Releases from the first public 2023.0 line through 2026.0.x use Newtonsoft.Json with `TypeNameHandling.All`; the later `SerializationBinder` only remaps assembly names, and `BindToType` resolves arbitrary wire-supplied types without an allow-list. Releases 2026.1.0 through 2026.1.18 use typeless MessagePack with `TypelessObjectResolver` and likewise instantiate arbitrary types. A same-user local process able to write to the pipe can send crafted messages that lead to arbitrary code execution with confidentiality, integrity and availability impacts inside the affected Visual Studio process. Default Windows pipe ACLs limit writers to the same logged-in user, so this does not escalate privileges or cross a security boundary; command-line and MSBuild-only builds do not use the channel. The maintained Metalama + PostSharp extension is affected from 2024.1 through 2026.1.4, while earlier Metalama-free PostSharp versions are unaffected. The retired Metalama and Caravela extensions remain affected and require removal or migration. The framework issue is fixed in versions 2025.1.18, 2026.0.25 and 2026.1.19; the maintained Metalama + PostSharp Visual Studio extension is fixed in version 2026.1.5. The retired Metalama and Caravela extensions require removal or migration.

Risk And Classification

Primary CVSS: v3.1 7.3 HIGH from [email protected]

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

Problem Types: CWE-502 | CWE-913 | CWE-502 CWE-502: Deserialization of Untrusted Data | CWE-913 CWE-913: Improper Control of Dynamically-Managed Code Resources

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.3HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
3.1CNADECLARED7.3HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Metalama Metalama affected >= 2023.0.101-rc, < 2025.1.18 Not specified
CNA Metalama Metalama affected >= 2025.2.0-preview, <= 2025.2.5-rc Not specified
CNA Metalama Metalama affected >= 2026.0.0-preview, < 2026.0.25 Not specified
CNA Metalama Metalama affected >= 2026.1.0-preview, < 2026.1.19 Not specified

References

ReferenceSourceLinkTags
github.com/metalama/Metalama/releases/tag/release/2026.0.25 [email protected] github.com
github.com/metalama/Metalama/commit/5b4ced29f2b25631cc2e44d05b0fd5fe838b... [email protected] github.com
github.com/metalama/Metalama/pull/1651 [email protected] github.com
github.com/metalama/Metalama/commit/d97f52e1b53ffe4176b2b05c56ffdf1ccd2f... [email protected] github.com
github.com/metalama/Metalama/security/advisories/GHSA-h26j-4vp7-x9w2 [email protected] github.com
github.com/metalama/Metalama/releases/tag/release/2026.1.19 [email protected] github.com
github.com/metalama/Metalama/releases/tag/release/2025.1.18 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report