CVE-2026-62847: Metalama · DEPRECATED: Insecure Temporary File
Affects MetalamaSource CVE Database V5
Not known to be exploited · CVSS 8.2 High · fixed in 2026.1.19 : patch Metalama soon.
Data as of 30 Oct 2026, 22:36 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 8.2 |
|---|
- Patch
- Available – fixed in 2026.1.19, 2026.0.25, 2025.1.18
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 30 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade Metalama and metalama/Metalama to 2026.1.19, 2026.0.25 or 2025.1.18.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| metalamaMetalama | Affected
| Fixed in
|
GitHubmetalama/Metalamapkg:github/metalama/MetalamaOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade Metalama to version 2025.1.18, 2026.0.25, or 2026.1.19 or later, where this issue is fixed. Avoid using insecure deployer-selected cache locations. No other mitigation is indicated by the vendor advisory.
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.
References
- github.com/metalama/Metalama/security/advisories/GHSA-m6wq-39m7-9xpp (opens in a new tab)
- github.com/metalama/Metalama/pull/1650 (opens in a new tab)
- github.com/metalama/Metalama/commit/09911349a916e82194b1cfaa6d0a38acad928fc9 (opens in a new tab)
- github.com/metalama/Metalama/commit/92c4feecfce86d18fcb007ab6d3a1b4383326a2e (opens in a new tab)
- github.com/metalama/Metalama/releases/tag/release/2025.1.18 (opens in a new tab)
- github.com/metalama/Metalama/releases/tag/release/2026.0.25 (opens in a new tab)
- github.com/metalama/Metalama/releases/tag/release/2026.1.19 (opens in a new tab)