Yamcs: Remote Code Execution via instance-template argument YAML injection (createInstance) (yamcs yamcs)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.78 % · percentile 56 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Awaiting Analysis
Description
Yamcs is a mission control framework. Prior to 5.12.8 and 5.13.2, Yamcs inserts templateArgs from POST /api/instances and PATCH /api/instances/{instance} into YAML through VarStatement.append in yamcs-core/src/main/java/org/yamcs/templating/VarStatement.java without YAML-context escaping. The rendered configuration is parsed by YamcsServer.createInstance and loaded by YamcsServerInstance, allowing an attacker to inject a services entry for org.yamcs.ProcessRunner. Deployments without security.yaml expose the operation through the guest superuser, while secured deployments require SystemPrivilege.CreateInstances. Successful exploitation executes commands as the Yamcs service account. This issue is fixed in versions 5.12.8 and 5.13.2.
Weaknesses (CWE)
- CWE-94 — Improper Control of Generation of Code
- CWE-470 — Use of Externally-Controlled Input to Select Classes or Code
- CWE-1336 — Improper Neutralization of Special Elements Used in a Template Engine
References
- https://github.com/yamcs/yamcs/security/advisories/GHSA-73mf-m39p-wpm9
- https://github.com/yamcs/yamcs/commit/549f295cf8c5496a5e799d6bec2432ef976c82aa
- https://github.com/yamcs/yamcs/commit/7192da1c49bdf5ab1d72e579a47766a7c43e87c8
- https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.8
- https://github.com/yamcs/yamcs/releases/tag/yamcs-5.13.2
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | CRITICAL 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | GitHub_M |
| CVSS 3.1 | CRITICAL 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-73mf-m39p-wpm9 — Yamcs vulnerable to Remote Code Execution via instance-template argument YAML injection (createInstance)
European references
- ENISA EUVD · EUVD-2026-67843
- GCVE · GCVE-0-2026-55559
Affected products
| Product | Versions |
|---|---|
| yamcs · yamcs | affected < 5.12.8 ; affected >= 5.13.0, < 5.13.2 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |