Yamcs: Server-Side Code Injection (RCE) via Janino Expression Engine in `JavaExprAlgorithmExecutionFactory`

Yamcs is a mission control framework. Prior to 5.12.7, a server-side code injection vulnerability existed in the Yamcs algorithm evaluation engine org.yamcs.algorithms.JavaExprAlgorithmExecutionFactory, which dynamically compiled and evaluated user-controlled algorithm text through the Janino compiler without enforcing a secure sandbox, so an authenticated user with the ChangeMissionDatabase privilege could override an existing algorithm's text via the mission database REST API and inject Java code (for example using java.lang.Runtime) to achieve remote code execution on the underlying host operating system. This issue is fixed in versions 5.12.7 and 5.13.0, which disable algorithm editing by default.