SSRF (Server-Side Request Forgery) in crawl4ai (CVE-2026-53755)
Summary
SSRF in crawl4ai (CVE-2026-53755). Confidential information can be exposed externally. Exploitable via browser_config. Mitigation: upgrade to 0.8.9 or later.
Original description
The description as published by the source.
Crawl4AI is an open-source LLM friendly web crawler & scraper. Prior to 0.8.9, the Docker API server applied its SSRF destination check to the crawl target URL only, not to the proxy address. An unauthenticated request could supply a proxy pointing at an internal IP and route the browser through it, reaching internal services and cloud-metadata endpoints, while using a perfectly valid crawl URL. The Docker API is unauthenticated by default. /crawl, /crawl/stream, and /crawl/job accept a browser_config (and crawler_config). The following all feed Chromium's egress and were unchecked: browser_config.proxy_config.server, browser_config.proxy (deprecated field), crawler_config.proxy_config.server, and --proxy-server / --proxy-pac-url / --proxy-bypass-list / --host-resolver-rules flags in browser_config.extra_args. This vulnerability is fixed in 0.8.9.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-53755 has been found in crawl4ai.
Attackers can target a specific entry point like browser_config over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.6/10.
What to do: upgrade crawl4ai to 0.8.9 or later.
If unsure, ask your IT team or search "crawl4ai CVE-2026-53755" on the vendor's site.
CVE-2026-53755 (crawl4ai) — CWE-918 / CVSS v3 8.6
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: browser_config / crawler_config / browser_config.proxy_config.server / browser_config.proxy
Patched: 0.8.9 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
SSRF (CWE-918) exists in crawl4ai. Attackers reach the vulnerable code path via browser_config without authentication.
Check the vendor advisory for the affected versions of crawl4ai. Attack surface: browser_config / crawler_config / browser_config.proxy_config.server / browser_config.proxy.
Severity: High (CVSS 8.6/10). Confidential information can be exposed externally.
Update to 0.8.9.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'crawl4ai' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'crawl4ai' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
crawl4aiを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade crawl4ai to 0.8.9ステージング環境で 0.8.9 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com