CVE-2026-46562: Spaceapplications Yamcs

Critical severity, CVSS 9.8. EPSS: 1% chance of exploitation in the next 30 days.

Yamcs is a mission control framework. Prior to 5.12.7, the Nashorn ScriptEngine used to evaluate user-supplied JavaScript algorithm text in yamcs-core/src/main/java/org/yamcs/algorithms/ScriptAlgorithmExecutorFactory.java was constructed without a ClassFilter, so a user with the ChangeMissionDatabase privilege could override an algorithm through the MdbOverrideApi.updateAlgorithm endpoint and supply JavaScript that reaches arbitrary Java classes (for example Java.type("java.lang.Runtime").getRuntime().exec(...)) to execute arbitrary OS commands as the Yamcs process; in the default configuration with no security.yaml the built-in guest user has superuser=true, making the issue reachable without authentication. This issue is fixed in versions 5.12.7 and 5.13.0, which disable algorithm editing by default.

Affected products

• Spaceapplications Yamcs: before 5.12.7 (fixed in 5.12.7)

Published 2026-07-16. Last modified 2026-07-20.