PraisonAI, a multi-agent teams system by MervinPraison, has a deserialization vulnerability (CWE-502) in its AgentService.loadAgentFromFile method prior to version 4.5.115. The method uses the js-yaml library to parse YAML files but does not disable dangerous tags such as !!js/function and !!js/undefined. This allows an attacker to craft a malicious YAML file that executes arbitrary JavaScript code when parsed. Exploitation requires uploading a malicious agent definition file via the API endpoint, resulting in remote code execution on the server. The vulnerability has a CVSS 3.1 base score of 9.8, indicating critical severity. The vulnerability is addressed in PraisonAI version 4.5.115.

Successful exploitation allows an unauthenticated attacker to achieve remote code execution on the server running PraisonAI, potentially leading to full system compromise, data theft, or service disruption. The vulnerability affects all versions prior to 4.5.115. There are no reports of known exploits in the wild at this time.

Upgrade PraisonAI to version 4.5.115 or later, where this vulnerability is fixed by disabling dangerous YAML tags during parsing. Since no official patch links or vendor advisory content are provided, confirm the upgrade path with the vendor's official release notes or security advisories. Until upgraded, restrict access to the API endpoint that accepts agent definition files to trusted users only to reduce exposure.