High severity · published Apr 3, 2026
CVE-2026-34939
PraisonAI: ReDoS via Unvalidated User-Controlled Regex in MCPToolIndex.search_tools()
7.5
CVSS
0.4%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PR
PraisonAI · MervinPraison
< 4.5.90 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34939
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34939
Exploit
https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-8w9j-hc3g-3g7f
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