PraisonAI: ReDoS via Unvalidated User-Controlled Regex in MCPToolIndex.search_tools()
Priority HIGH 66CWE-1333Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-1333.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00418 36th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed PraisonAI (MervinPraison): 4.5.90praisonai (PyPI): 4.5.90
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| MervinPraison | PraisonAI | before 4.5.90 | 4.5.90 | Patch available | CNA |
| — | praisonai (PyPI) | before 4.5.90 | 4.5.90 | Patch available | GHSA-8w9j-hc3g-3g7f |
- PraisonAI VendorMervinPraison Affected before 4.5.90 Fixed in 4.5.90 Patch available CNA
- praisonai (PyPI) Vendor— Affected before 4.5.90 Fixed in 4.5.90 Patch available GHSA-8w9j-hc3g-3g7f
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:praison:praisonai:*:*:*:*:*:*:*:* | before 4.5.90 | Vulnerable | MervinPraison |
- cpe:2.3:a:praison:praisonai:*:*:*:*:*:*:*:* Versions before 4.5.90 Vulnerable ·MervinPraison
Remediation
- Fix · CNA PraisonAI (MervinPraison) Fixed in 4.5.90
- Fix · GHSA-8w9j-hc3g-3g7f praisonai (PyPI) Fixed in 4.5.90 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-34939
- 2026-10-03 Alias added: GHSA-8w9j-hc3g-3g7f
References
More MervinPraison Praisonai vulnerabilities
- TI-2026-30083 Incomplete fix for CVE-2026-34935: Command Injection in MervinPraison/PraisonAI CVSS 3.1CRITICAL 9.8
- TI-2026-29070 PraisonAI: Critical RCE via `type: job` workflow YAML CVSS 3.1CRITICAL 9.8
- TI-2026-28940 PraisonAI has Server-Side Request Forgery via Unvalidated webhook_url in Jobs API CVSS 3.1CRITICAL 10.0
- TI-2026-28768 PraisonAI Affected by Remote Code Execution via YAML Deserialization in Agent Definition Loading CVSS 3.1CRITICAL 9.8
- TI-2026-27159 PraisonAI: OS Command Injection in MCPHandler.parse_mcp_command() CVSS 3.1CRITICAL 9.8
- TI-2026-27158 PraisonAI: Second-Order SQL Injection in `get_all_user_threads` CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-34939 · CVE Program
- CVE-2026-34939 · NVD
- FIRST EPSS
- GHSA-8w9j-hc3g-3g7f · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences