CVE-2026-39890

PraisonAI Affected by Remote Code Execution via YAML Deserialization in Agent Definition Loading

PraisonAI is a multi-agent teams system. Prior to 4.5.115, the AgentService.loadAgentFromFile method uses the js-yaml library to parse YAML files without disabling dangerous tags (such as !!js/function and !!js/undefined). This allows an attacker to craft a malicious YAML file that, when parsed, executes arbitrary JavaScript code. An attacker can exploit this vulnerability by uploading a malicious agent definition file via the API endpoint, leading to remote code execution (RCE) on the server. This vulnerability is fixed in 4.5.115.

Affected

MervinPraison · PraisonAI

CVSS v3.1 GITHUB

9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

0.81% chance of exploitation in the next 30 days, 56th percentile

Published

2026-04-08

Updated

2026-04-09

Proof-of-concept exploits (1)

• advisories/GHSA-32vr-5gcf-3pw2

Security advisories

• MervinPraison/PraisonAI/security/advisories/GHSA-32vr-5gcf-3pw2

References

• CVE Record
• NVD entry