PT-2026-53188 · Pypi · Crawl4Ai

Published

2026-06-18

·

Updated

2026-06-18

CVSS v3.1

8.6

High

VectorAV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Summary

The Docker API server applied its SSRF destination check (validate url destination) on the non-streaming /crawl path but not on the streaming path. handle stream crawl request passed seed URLs straight to the crawler with no destination validation. A remote, unauthenticated client could call POST /crawl/stream (or POST /crawl with crawler config.stream=true, which short-circuits to the same handler) with a URL pointing at an internal, private, or link-local address; the server fetched it and streamed the response body back. The Docker API is unauthenticated by default.

Affected paths

POST /crawl/stream, and POST /crawl with crawler config.stream=true (both route to handle stream crawl request, deploy/docker/api.py).

Impact

Unauthenticated read server-side request forgery: an attacker reads internal-only services and cloud-metadata endpoints (e.g. http://169.254.169.254/ for IAM credentials), with the response body streamed back. This is the same class and severity as the project's prior "SSRF via Direct Crawl Endpoints" advisory; /crawl/stream is part of that endpoint family and was never covered by the destination check.

Fix

handle stream crawl request now validates every seed URL's destination with the same global-routability check as handle crawl request, before any fetch. The SSRF regression test was hardened to assert per-handler coverage (including the streaming handler) rather than a bare occurrence count, which previously let this gap pass.

Workarounds

  • Upgrade to the patched version (0.9.0).
  • Enable authentication and restrict who can reach the API (note: this does not constrain which URL the API fetches).
  • Restrict the container's outbound network access (egress firewall / no metadata route).

Credits

KOH Jun Sheng - reported the streaming-path SSRF with a runnable PoC and noted the count-based regression test that masked it, plus the shared root cause with redirect/deep-crawl link following.

Fix

SSRF

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Weakness Enumeration

CWE-918

Related Identifiers

GHSA-WM69-2PC3-RMMF

Affected Products

Crawl4Ai