CVE-2026-34953
CRITICALCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Lifecycle Timeline
3Description
### Summary `OAuthManager.validate_token()` returns `True` for any token not found in its internal store, which is empty by default. Any HTTP request to the MCP server with an arbitrary Bearer token is treated as authenticated, granting full access to all registered tools and agent capabilities. ### Details `oauth.py:364` (source) -> `oauth.py:374` (loop miss) -> `oauth.py:381` (sink) ```python # source def validate_token(self, token: str) -> bool: for stored_token in self._tokens.values(): if stored_token.access_token == token: return not stored_token.is_expired() # sink -- _tokens is empty by default, loop never executes, falls through return True ``` ### PoC ```bash # install: pip install -e src/praisonai # start server: praisonai mcp serve --transport http-stream --port 8080 curl -s -X POST http://127.0.0.1:8080/mcp \ -H "Authorization: Bearer fake_token_abc123" \ -H "Content-Type: application/json" \ -d '{"jsonrpc":"2.0","method":"tools/list","id":1}' # expected output: 200 OK with full tool list (50+ tools) # including praisonai.agent.run, praisonai.workflow.run, praisonai.containers.file_write ``` ### Impact Any unauthenticated attacker with network access to the MCP HTTP server can call all registered tools including agent execution, workflow runs, container file read/write, and skill loading. The server binds to `0.0.0.0` by default with no API key required. ### Suggested Fix ```python def validate_token(self, token: str) -> bool: for stored_token in self._tokens.values(): if stored_token.access_token == token: return not stored_token.is_expired() # Unknown tokens must be rejected. # For external/JWT tokens, call the introspection endpoint here before returning. return False ```
Analysis
Authentication bypass in PraisonAI MCP server (Python package praisonai) allows remote, unauthenticated attackers to execute arbitrary agents, workflows, and file operations with zero authentication. The OAuthManager.validate_token() method incorrectly returns True for any token when its internal token store is empty (default state), treating all HTTP requests with arbitrary Bearer tokens as authenticated. …
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Remediation
Within 24 hours: Immediately inventory all systems running praisonai package and isolate affected instances from production environments or public networks. Within 7 days: Contact PraisonAI project maintainers for patch timeline; implement temporary mitigation by deploying network-level access controls (firewall rules, reverse proxy authentication) to restrict MCP server access to trusted networks only. …
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External POC / Exploit Code
Leaving vuln.today
GHSA-98f9-fqg5-hvq5