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CVE-2026-34939

HIGH CVSS 3.1: 7.5 EPSS 0.02%
Updated Apr 09, 2026
Python
Parameter Value
CVSS 7.5 (HIGH)
Affected Versions before 4.5.90
Fixed In 4.5.90
Type CWE-1333 (Inefficient Regular Expression Complexity / ReDoS)
Vendor Python
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Praison Praisonai
cpe:2.3:a:praison:praisonai:*:*:*:*:*:*:*:*
4.5.90