Description
Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. Prior to 2025.1.18, 2026.0.25 and 2026.1.19, Metalama.Framework and Metalama.Tool load and execute compile-time assemblies, auxiliary executable tools and embedded helper assemblies from predictable temporary directories. On `Linux` and `macOS`, the default `Path.GetTempPath()` location is world-writable, and existing artifacts are trusted based on sentinel or `.completed` marker files rather than integrity verification. A local unprivileged user on a shared machine or CI/build agent can pre-create the deterministic directory structure and plant a malicious DLL with the matching sentinel. When a higher-privileged developer or build account subsequently builds, Metalama skips regeneration and executes the planted artifact in the compiler, IDE or MSBuild process as the building user. This permits cross-user privilege escalation, reading source and secrets, supply-chain tampering with build output, or disrupting builds. Default Windows per-user temporary directories are protected by ACLs and are not affected. Deployer-selected insecure cache locations are outside the vulnerability's scope. This issue is fixed in versions 2025.1.18, 2026.0.25 and 2026.1.19.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
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| metalama | Metalama | affected |
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Remediation
No solution or workaround provided in the CVE record.
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Tracking
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Advisories
| Source | ID | Title |
|---|---|---|
 Github GHSA |
GHSA-m6wq-39m7-9xpp | Metalama allows local code execution through DLL planting in shared temporary directories |
References
History
Fri, 30 Oct 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Metalama is a Roslyn-based open-source patterns and architecture toolkit for C#. Prior to 2025.1.18, 2026.0.25 and 2026.1.19, Metalama.Framework and Metalama.Tool load and execute compile-time assemblies, auxiliary executable tools and embedded helper assemblies from predictable temporary directories. On `Linux` and `macOS`, the default `Path.GetTempPath()` location is world-writable, and existing artifacts are trusted based on sentinel or `.completed` marker files rather than integrity verification. A local unprivileged user on a shared machine or CI/build agent can pre-create the deterministic directory structure and plant a malicious DLL with the matching sentinel. When a higher-privileged developer or build account subsequently builds, Metalama skips regeneration and executes the planted artifact in the compiler, IDE or MSBuild process as the building user. This permits cross-user privilege escalation, reading source and secrets, supply-chain tampering with build output, or disrupting builds. Default Windows per-user temporary directories are protected by ACLs and are not affected. Deployer-selected insecure cache locations are outside the vulnerability's scope. This issue is fixed in versions 2025.1.18, 2026.0.25 and 2026.1.19. | |
| Title | Metalama: Local code execution via DLL planting in world-writable temporary directories (Linux/macOS) | |
| Weaknesses | CWE-377 CWE-427 |
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| Metrics |
cvssV3_1
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Subscriptions
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-10-30T20:23:50.882Z
Reserved: 2026-07-14T21:10:50.031Z
Link: CVE-2026-62847
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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