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Response snapshot Oct 30, 2026, 23:06 UTC

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VulnerabilityCVE-2026-62848

Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#.

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.

At a glance

Exploited
Not known
Severity
7.3 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-62848 (opens a new tab)

What happened

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.

Continue reading

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.

Scores and how they were measured

CVSS base severity

7.3

Version 3.1As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Sources

  1. Primary source

    NVD CVE-2026-62848 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 30). Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. (CVE-2026-62848). https://kevwire.com/record/CVE-2026-62848

MLA

"Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. (CVE-2026-62848)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-62848.

Chicago

KEVWire. "Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. (CVE-2026-62848)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-62848.

Evidence summary (plain text)

Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. (Oct 30, 2026).
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)}.
CVSS 7.3 (version 3.1; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-62848).
Sources:
NVD CVE-2026-62848: https://nvd.nist.gov/vuln/detail/CVE-2026-62848
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T20:56:01.746Z&lastModEndDate=2026-10-30T22:30:56.395Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T20:20:59.645Z&lastModEndDate=2026-10-30T21:55:57.278Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T19:46:09.038Z&lastModEndDate=2026-10-30T21:20:56.675Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-62848.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 30, 2026, 22:30 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail