CVE-2026-55559

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...

Improper Neutralization of Special Elements Used in a Template Engine

Overview Affected versions of this package are vulnerable to Improper Neutralization of Special Elements Used in a Template Engine via the templateArgs parameter in the createInstance process. An attacker can execute arbitrary commands on the host system by injecting malicious YAML content that...

Yamcs vulnerable to Remote Code Execution via instance-template argument YAML injection (createInstance)

Summary templateArgs sent to POST /api/instances and PATCH /api/instances/instance are written into the rendered instance config as raw text, then parsed as YAML and loaded. Yamcs instantiates each services: entry by its class:, so injecting YAML through a template arg lets you add a services:...

CVE-2026-55559 Yamcs: Remote Code Execution via instance-template argument YAML injection (createInstance)

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...