CVE-2026-34939 MEDIUM

CVE-2026-34939: PraisonAI: ReDoS via Unvalidated User-Controlled Regex in MCPToolIndex.search_tools()

Vendor Mervinpraison
Product PraisonAI
Weakness CWE-1333
Published April 3, 2026
Last update April 6, 2026
View on NVD All CVEs

CVSS base score

6.5/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality None
Integrity None

CVSS vector

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

What the vulnerability does

01Description

PraisonAI is a multi-agent teams system. Prior to version 4.5.90, MCPToolIndex.search_tools() compiles a caller-supplied string directly as a Python regular expression with no validation, sanitization, or timeout. A crafted regex causes catastrophic backtracking in the re engine, blocking the Python thread for hundreds of seconds and causing a complete service outage. This issue has been patched in version 4.5.90.

Key dates

02Disclosure timeline

April 3, 2026 CVE published
April 6, 2026 Record updated