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

Quick assessment

Affected
MervinPraison PraisonAI
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

PraisonAI是Mervin Praison个人开发者的一个低代码多智能体协作框架。 PraisonAI 4.5.90之前版本存在安全漏洞，该漏洞源于MCPToolIndex.search_tools函数将调用者提供的字符串直接编译为正则表达式，未经验证、清理或设置超时，可能导致正则表达式拒绝服务。

CVSS 6.5 · Medium EPSS 0.40% · P34

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking
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I. Basic Information for CVE-2026-34939

Vulnerability Information
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Vulnerability Title
PraisonAI: ReDoS via Unvalidated User-Controlled Regex in MCPToolIndex.search_tools()
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
CWE-1333
Source: CVE Program / CVE List V5
Vulnerability Title
PraisonAI 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
PraisonAI是Mervin Praison个人开发者的一个低代码多智能体协作框架。 PraisonAI 4.5.90之前版本存在安全漏洞，该漏洞源于MCPToolIndex.search_tools函数将调用者提供的字符串直接编译为正则表达式，未经验证、清理或设置超时，可能导致正则表达式拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
MervinPraison PraisonAI < 4.5.90 -

II. Public POCs for CVE-2026-34939

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III. Intelligence Information for CVE-2026-34939

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Same Patch Batch · MervinPraison · 2026-04-03 · 10 CVEs total

CVE-2026-34938 10.0 CRITICAL PraisonAI: Python Sandbox Escape via str Subclass startswith() Override in execute_code
CVE-2026-34934 9.8 CRITICAL PraisonAI: Second-Order SQL Injection in `get_all_user_threads`
CVE-2026-34935 9.8 CRITICAL PraisonAI: OS Command Injection in MCPHandler.parse_mcp_command()
CVE-2026-34952 9.1 CRITICAL PraisonAI: Missing Authentication in WebSocket Gateway
CVE-2026-34953 9.1 CRITICAL PraisonAI: Authentication Bypass in OAuthManager.validate_token()
CVE-2026-34955 8.8 HIGH PraisonAI: Sandbox Escape via shell=True and Bypassable Blocklist in SubprocessSandbox
CVE-2026-34954 8.6 HIGH PraisonAI: SSRF in FileTools.download_file() via Unvalidated URL
CVE-2026-34937 7.8 HIGH PraisonAI: Shell Injection in run_python() via Unescaped $() Substitution
CVE-2026-34936 7.7 HIGH PraisonAI: SSRF via Unvalidated api_base in passthrough() Fallback

IV. Related Vulnerabilities

Same product: PraisonAI
Same vendor: MervinPraison
Same weakness: CWE-1333

V. Comments for CVE-2026-34939

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