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Vulnerability record · CVE-2026-34939 · published 3 April 2026

CVE-2026-34939: Praisonai inefficient regular expression (redos) vulnerability

Praison · 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.

7.5 CVSS 3.1 High EPSS 0.45% · top 63.6% CWE-1333 · Inefficient regular expression (ReDoS)
7.5CVSS 3.1 base score
0.45%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References, 1 tagged exploit
24 Jul 2026Last modified by NVD

Description

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-8w9j-hc3g-3g7f ExploitVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-34939), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.