CVE-2021-43578: Agent-to-controller security bypass in Jenkins Squash TM Publisher (Squash4Jenkins) Plugin allows writing arbitrary files

The vulnerability stems from insecure implementation of Jenkins' agent-to-controller communication pattern. The plugin's file writing functionality (1) lacks input validation on file paths, and (2) accepts arbitrary JSON content from untrusted agents. Based on Jenkins plugin architecture patterns and the CWE-693 description, these functions would typically be responsible for handling FileCallable operations that write results from agents to the controller. The high confidence comes from the direct match between the vulnerability description (unvalidated agent-controlled file writes) and common Jenkins Remoting implementation patterns in plugin code.