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CVE-2026-57571 critical CVSS 9.6

Path Traversal in crawl4ai (CVE-2026-57571)

Summary

Path traversal in crawl4ai (CVE-2026-57571). Successful exploitation can lead to full system takeover. Exploitable via AsyncHTTPCrawlerStrategy. Mitigation: upgrade to 0.9.0 or later.

Original description

The description as published by the source.

Summary

When the crawler saves a downloaded file, the destination filename was taken from attacker-influenced input and joined to the downloads directory with no confinement. A filename containing an absolute path (e.g. /etc/cron.d/evil) or ../ traversal escaped the downloads directory, giving an arbitrary file write with attacker-controlled contents. Because the written bytes are attacker-controlled, this escalates to remote code execution (overwriting a shell rc-file, ~/.ssh/authorized_keys, a cron entry, or a Python module on the import path).

Affected paths

Two download sinks in crawl4ai/async_crawler_strategy.py:

  • HTTP crawler (AsyncHTTPCrawlerStrategy): the filename is parsed from the response Content-Disposition header by _extract_filename() and written via aiofiles.open(filepath, 'wb'). Reachable directly via the SDK, and via the unauthenticated Docker /crawl endpoint when an HTTPCrawlerConfig is supplied.
  • Browser crawler (AsyncPlaywrightCrawlerStrategy): the download's suggested_filename (controllable by the visited page) is joined to downloads_path and written via download.save_as().

The HTTP-strategy sink is reachable pre-auth on the default Docker deployment; both are reachable for SDK users simply by crawling an attacker-controlled URL. The default Playwright crawl path that does not trigger a download is unaffected.

Impact

Arbitrary file write with attacker-controlled content as the user running the crawler, escal…

Source: NIST National Vulnerability Database 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-2026-57571 has been found in crawl4ai.
Attackers can target a specific entry point like AsyncHTTPCrawlerStrategy over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.6/10.
What to do: upgrade crawl4ai to 0.9.0 or later.
If unsure, ask your IT team or search "crawl4ai CVE-2026-57571" on the vendor's site.

CVE-2026-57571 (crawl4ai) — CWE-22 / CVSS v3 9.6
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: AsyncHTTPCrawlerStrategy / HTTPCrawlerConfig / AsyncPlaywrightCrawlerStrategy / suggested_filename
Patched: 0.9.0 — 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.

❓ What is the problem

Path traversal (CWE-22) exists in crawl4ai. Attackers reach the vulnerable code path via AsyncHTTPCrawlerStrategy without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of crawl4ai. Attack surface: AsyncHTTPCrawlerStrategy / HTTPCrawlerConfig / AsyncPlaywrightCrawlerStrategy / suggested_filename.

🔥 Severity

Severity: Critical (CVSS 9.6/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 0.9.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

  1. 1
    Identify 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。

  2. 2
    Apply patch patch 
    Upgrade crawl4ai to 0.9.0

    ステージング環境で 0.9.0 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。

  3. 3
    Post-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

PyPI crawl4ai
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.0"}]}]

References

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