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.
Summary
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.
Affected paths
/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.serverbrowser_config.proxy(deprecated field)crawler_config.proxy_config.server--proxy-server/--proxy-pac-url/--proxy-bypass-list/--host-resolver-rulesflags inbrowser_config.extra_args
Attack
An attacker sends /crawl with a benign, validation-passing URL but a proxy_config.server pointing at an internal IP. Chromium routes all requests through that proxy. For plain-HTTP targets the proxy receives the full request and can return any content, which is then returned verbatim in the crawl result (results[0].html / cleaned_html / markdown). In a real deployment the proxy would be an attacker-controlled server pointing at cloud metadata (e.g. AWS IMDSv1 at 169.254.169.254) to retrieve IAM credential tokens.
Impact
Unauthenticated server-side request forgery to internal services and cloud-metadata endpoints, with the response returned to the attacker.
##…
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 nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com