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

April 1, 2026 (updated April 6, 2026)

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.

References

github.com/MervinPraison/PraisonAI
github.com/MervinPraison/PraisonAI/security/advisories/GHSA-8w9j-hc3g-3g7f
github.com/advisories/GHSA-8w9j-hc3g-3g7f
nvd.nist.gov/vuln/detail/CVE-2026-34939

Code Behaviors & Features

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