Review reviewHigh

CVE-2026-34939

MervinPraison PraisonAI, praisonai

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.

CVSS: 7.5
EPSS: 0.40%
CISA KEV: Not listed
Published: 2026.04.04

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.40%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: MervinPraison PraisonAI, praisonai
Affected versions: >= < 4.5.90, < 4.5.90
Fixed versions: 4.5.90

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that MervinPraison PraisonAI, praisonai and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-1333