{"id":"CVE-2026-62847","published":"2026-10-30T21:17:13.807","lastModified":"2026-10-30T23:17:12.923","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.","cvssScore":8.2,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H","cwes":["CWE-377","CWE-427"],"vendors":[],"products":[],"references":[{"url":"https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9","tags":[]},{"url":"https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e","tags":[]},{"url":"https://github.com/metalama/Metalama/pull/1650","tags":[]},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2025.1.18","tags":[]},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2026.0.25","tags":[]},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2026.1.19","tags":[]},{"url":"https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp","tags":[]}],"exploitRefs":[{"url":"https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9","tags":[]},{"url":"https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e","tags":[]},{"url":"https://github.com/metalama/Metalama/pull/1650","tags":[]},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2025.1.18","tags":[]},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2026.0.25","tags":[]},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2026.1.19","tags":[]},{"url":"https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp","tags":[]}],"hasPoc":true,"ai":null}