CVE-2026-39890 CRITICAL

CVE-2026-39890: PraisonAI Affected by Remote Code Execution via YAML Deserialization in Agent Definition Loading

Vendor Mervinpraison
Product PraisonAI
Weakness CWE-502 · Unsafe deserialization
Published April 8, 2026
Last update April 9, 2026

CVSS base score

9.8/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 8, 2026 CVE published
April 9, 2026 Record updated