CVE-2026-57573

Description

### 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.

How to fix CVE-2026-57573

To remediate CVE-2026-57573, upgrade the affected package to a fixed version below.

• —upgrade to 0.9.0 or later
• —upgrade to 0.9.0 or later

Is CVE-2026-57573 being exploited?