Crawl4AI: Denial of service in Docker API server (CVE-2026-119119)
Crawl4AI versions prior to 0.9.5 are vulnerable to a denial-of-service attack due to improper validation of delay parameters in untrusted CrawlerRunConfig requests, allowing unauthenticated attackers to exhaust browser page resources.
CVE search metadata
CVE search record: CVE-2026-119119. Severity: high. CVSS: 7.5. KEV: no. Product: Crawl4AI (< 0.9.5), Crawl4AI (0.9.0 <= version < 0.9.5). Brief: Crawl4AI: Denial of service in Docker API server (CVE-2026-119119). Brief link: https://feed.craftedsignal.io/briefs/2026-10-crawl4ai-dos/
CVE search record: CVE-2026-119120. Severity: high. CVSS: 7.5. KEV: no. Product: Crawl4AI (< 0.9.5), Crawl4AI (0.9.0 <= version < 0.9.5). Brief: Crawl4AI: Denial of service in Docker API server (CVE-2026-119119). Brief link: https://feed.craftedsignal.io/briefs/2026-10-crawl4ai-dos/
Triage facts
Revision 2- Applicability
- Crawl4AI (< 0.9.5), Crawl4AI (0.9.0 <= version < 0.9.5)
- Evidence
- Unknown
- Severity
- High
- Action
- Elevated
- Sources
- 2 public sources
- Freshness
- Revision 2Oct 29, 18:44 UTC
- Vulnerabilities
- 2 CVEs
- Source quality
- A1Likely
Revision history 1 entry · Revision 2
- Revision 2
severity → high; added CVE-2026-119120
Changed: affected_products, cves, lastmod, priority, priority_score, references, severity, updates
Sources: 1
Crawl4AI versions before 0.9.5 contain a denial of service vulnerability in the Docker API server component. The function _clamp_untrusted() fails to cap the delay_before_return_html, mean_delay, and max_range fields within untrusted CrawlerRunConfig request bodies. By submitting specially crafted HTTP requests to the /crawl or /crawl/stream endpoints, an unauthenticated attacker can supply excessively large values for these parameters. This forces the application to hold browser pages or stall the rate limiter indefinitely, leading to resource exhaustion of the browser page pool and preventing legitimate crawling operations.
Impact
Successful exploitation allows an unauthenticated attacker to render the Crawl4AI service unavailable for legitimate users by exhausting the browser page pool.
Recommendation
- Upgrade Crawl4AI to version 0.9.5 or later to resolve the improper input validation in the Docker API server.
- Implement request rate limiting and input validation at the edge (e.g., WAF or API Gateway) for the
/crawland/crawl/streamendpoints if an immediate upgrade is not possible. - Monitor logs for HTTP POST requests to
/crawlor/crawl/streamcontaining unusually large values in the specified JSON fields.
Immediate actions
Upgrade Crawl4AI instances to 0.9.5 or later.
Threat Hunt
Identify HTTP POST requests to /crawl or /crawl/stream with atypically high values for delay_before_return_html, mean_delay, or max_range.
Data: Web server access logs or API gateway request logs containing JSON request bodies.
Mitigations
Apply input validation or rate limiting at the WAF/API Gateway layer for /crawl and /crawl/stream.
CVE-2026-119119