{"id":"CVE-2026-62847","sourceIdentifier":"security-advisories@github.com","published":"2026-10-30T21:17:13.807","lastModified":"2026-11-02T19:35:33.347","vulnStatus":"Deferred","cveTags":[],"descriptions":[{"lang":"en","value":"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."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"metalama","product":"Metalama","versions":[{"version":"< 2025.1.18","status":"affected"},{"version":">= 2025.2.0-preview, <= 2025.2.5-rc","status":"affected"},{"version":">= 2026.0.0-preview, < 2026.0.25","status":"affected"},{"version":">= 2026.1.0-preview, < 2026.1.19","status":"affected"}]}]}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"REQUIRED","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.5,"impactScore":6.0}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-30T21:21:14.933972Z","id":"CVE-2026-62847","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-377"},{"lang":"en","value":"CWE-427"}]}],"references":[{"url":"https://github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9","source":"security-advisories@github.com"},{"url":"https://github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e","source":"security-advisories@github.com"},{"url":"https://github.com/metalama/Metalama/pull/1650","source":"security-advisories@github.com"},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2025.1.18","source":"security-advisories@github.com"},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2026.0.25","source":"security-advisories@github.com"},{"url":"https://github.com/metalama/Metalama/releases/tag/release/2026.1.19","source":"security-advisories@github.com"},{"url":"https://github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp","source":"security-advisories@github.com"}]}