CVE-2026-56260

Crawl4AI before 0.8.7 contains an authentication bypass vulnerability in the monitor router endpoints that allows unauthenticated attackers to access destructive operations. Remote attackers can invoke the /monitor/actions/cleanup endpoint and manipulate monitoring state without authentication, causing service disruption.

Crawl4AI before 0.8.7 contains a stored cross-site scripting vulnerability in the monitor dashboard that renders crawl URLs and error messages via innerHTML without escaping. An attacker can submit a crafted crawl request with malicious markup that executes in an operator's browser when viewing the dashboard.

Crawl4AI before 0.8.7 contains an arbitrary JavaScript execution vulnerability in the Docker API server's /execute_js endpoint, which accepts and executes arbitrary user-supplied JavaScript in the server's browser context with --disable-web-security enabled. An attacker can execute arbitrary JavaScript and, combined with the browser's relaxed security settings, perform server-side request forgery against internal services.

Crawl4AI before 0.8.7 contains an authentication bypass vulnerability due to a hardcoded default JWT signing key in the Docker API server. Attackers who know the default key can forge valid authentication tokens for any user, bypassing authentication and gaining full access to protected functionality.

Crawl4AI before 0.8.7 contains a server-side request forgery vulnerability in the /crawl, /crawl/stream, /md, and /llm endpoints that fetch arbitrary user-supplied URLs without validation. Unauthenticated attackers can bypass the internal-address blocklist using IPv6-mapped IPv4 addresses to reach internal services and cloud metadata endpoints.

Summary

Multiple security vulnerabilities in the Crawl4AI Docker API server affecting endpoints for crawling, markdown/LLM extraction, screenshots, PDFs, webhooks, monitoring, JavaScript execution, and configuration.

Vulnerabilities

1. Arbitrary File Write via /screenshot and /pdf (CWE-22, CVSS 9.1)

The output_path parameter accepts arbitrary filesystem paths with no validation. An attacker can overwrite server files (DoS) or write to any appuser-writable location.

Fix: Added validate_output_path() restricting writes to CRAWL4AI_OUTPUT_DIR (/tmp/crawl4ai-outputs by default). Added Pydantic field_validator rejecting .. traversal sequences.

2. SSRF via Webhook URL (CWE-918, CVSS 8.6)

Webhook URLs in /crawl/job and /llm/job accept internal/private IPs with no validation, enabling Server-Side Request Forgery against cloud metadata endpoints (169.254.169.254), internal services, and Docker networks.

Fix: Added validate_webhook_url() with blocklist for RFC 1918, loopback, link-local, cloud metadata IPs and hostnames. Validation at both job submission and send time. Explicit follow_redirects=False.

3. Authentication Bypass on Monitor Endpoints (CWE-306, CVSS 6.5)

The monitor router was mounted without token_dep dependency, making all monitoring endpoints (including destructive ones like /monitor/actions/cleanup) accessible without authentication.

Fix: Added dependencies=[Depends(token_dep)] to monitor router. Added explicit token check on WebSocket /monitor/ws endpoint.

4. Stored XSS in Monitor Dashboard (CWE-79, CVSS 6.1)

URLs and error messages rendered in the monitor dashboard via innerHTML without escaping, enabling stored XSS via crafted crawl URLs.

Fix: Server-side html.escape() on URL and error storage. Client-side escapeHtml() wrapper on all innerHTML template injections.

5. Arbitrary JavaScript Execution via /execute_js (CWE-94, CVSS 8.1)

The /execute_js endpoint accepts and executes arbitrary JavaScript in the server's browser with --disable-web-security enabled, combining arbitrary JS execution with SSRF capability.

Fix: Disabled by default via CRAWL4AI_EXECUTE_JS_ENABLED env var. Added SSRF blocklist on destination URL. Removed --disable-web-security from default browser args.

6. Hardcoded JWT Secret Key (CWE-798, CVSS 9.8)

The JWT signing key defaults to "mysecret" in the public source code, allowing anyone to forge valid authentication tokens.

Fix: Removed default value. Added startup validation rejecting weak/short secrets. Auto-generates ephemeral key when JWT enabled but no key set.

7. SSRF via Direct Crawl Endpoints /crawl, /md, /llm (CWE-918, CVSS 8.6)

The primary crawl entry points (/crawl, /crawl/stream, /md, /llm) fetch arbitrary user-supplied URLs with no destination validation, enabling Server-Side Request Forgery against internal services, Docker networks, and cloud metadata endpoints (169.254.169.254). A blocklist that only inspects the literal hostname is additionally bypassable via IPv6-mapped IPv4 addresses (e.g. [::ffff:169.254.169.254], [::ffff:10.0.0.1]), which resolve to the blocked private/metadata ranges but evade a naive string check.

Fix: Added URL destination validation on all crawl/md/llm entry points, reusing the SSRF blocklist (RFC 1918, loopback, link-local, cloud-metadata IPs and hostnames). IPv6-mapped IPv4 addresses are normalized to their IPv4 form before the blocklist check, closing the mapping bypass. raw:// URLs are skipped. Validation applies at request entry, not only at fetch time.

Workarounds

1. Upgrade to the patched version (recommended)
2. Set CRAWL4AI_API_TOKEN to enable authentication
3. Set a strong SECRET_KEY (min 32 chars) if using JWT
4. Restrict network access to the Docker API

Credits

• Jeongbean Jeon - file write, SSRF, monitor auth bypass, stored XSS
• wulonchia - file write via output_path (independent…

Crawl4AI before 0.8.7 contains an authentication bypass vulnerability due to a hardcoded default JWT signing key in the Docker API server. Attackers who know the default key can forge valid authentication tokens for any user, bypassing authentication and gaining full access to protected functionality.

Crawl4AI before 0.8.7 contains an authentication bypass vulnerability in the monitor router endpoints that allows unauthenticated attackers to access destructive operations. Remote attackers can invoke the /monitor/actions/cleanup endpoint and manipulate monitoring state without authentication, causing service disruption.

Crawl4AI before 0.8.7 contains a stored cross-site scripting vulnerability in the monitor dashboard that renders crawl URLs and error messages via innerHTML without escaping. An attacker can submit a crafted crawl request with malicious markup that executes in an operator's browser when viewing the dashboard.

Crawl4AI before 0.8.7 contains an authentication bypass vulnerability due to a hardcoded default JWT signing key in the Docker API server. Attackers who know the default key can forge valid authentication tokens for any user, bypassing authentication and gaining full access to protected functionality.

Crawl4AI before 0.8.7 contains a server-side request forgery (SSRF) vulnerability in the Docker API server's /crawl/job and /llm/job endpoints, which accept webhook URLs without destination validation. An attacker can supply webhook URLs pointing to private or internal IP ranges, Docker networks, or cloud metadata endpoints (e.g. 169.254.169.254), causing the server to make requests to internal services and potentially expose cloud metadata.

Crawl4AI before 0.8.7 contains an arbitrary file write vulnerability in the Docker API server's /screenshot and /pdf endpoints. The output_path parameter accepts arbitrary filesystem paths without validation, allowing an attacker to supply absolute or path-traversal values to write to any location writable by the application's user, overwriting server files and causing denial of service.

Crawl4AI before 0.8.7 contains a server-side request forgery vulnerability in the /crawl, /crawl/stream, /md, and /llm endpoints that fetch arbitrary user-supplied URLs without validation. Unauthenticated attackers can bypass the internal-address blocklist using IPv6-mapped IPv4 addresses to reach internal services and cloud metadata endpoints.

Crawl4AI before 0.8.7 contains an arbitrary JavaScript execution vulnerability in the Docker API server's /execute_js endpoint, which accepts and executes arbitrary user-supplied JavaScript in the server's browser context with --disable-web-security enabled. An attacker can execute arbitrary JavaScript and, combined with the browser's relaxed security settings, perform server-side request forgery against internal services.