CVE-2026-109239
Received Received - Intake

Blind SSRF in Crawl4AI via RobotsParser.can_fetch

Publication date: 2026-10-12

Last updated on: 2026-10-12

Assigner: VulnCheck

Description
Crawl4AI before 0.9.4 contains a blind server-side request forgery vulnerability in RobotsParser.can_fetch that lets unauthenticated attackers bypass Docker server egress controls. Attackers can enable check_robots_txt and use redirects or DNS rebinding to reach internal, loopback, or cloud-metadata addresses for service discovery.

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Meta Information

Published
2026-10-12
Last Modified
2026-10-12
Generated
2026-10-12
AI Q&A
2026-10-12
EPSS Evaluated
N/A
NVD
CVE-2026-109239
EUVD
EUVD-2026-97683

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
unclecode crawl4ai 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

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Executive Summary

CVE-2026-109239 is a blind Server-Side Request Forgery (SSRF) vulnerability in the crawl4ai library affecting versions up to 0.9.3. It exists in the RobotsParser.can_fetch function where the robots.txt fetch bypasses Docker server egress controls. Attackers can exploit this to make outbound requests to internal, private, or cloud-metadata addresses without authentication. The vulnerability allows service discovery through redirects or DNS rebinding.

Detection Guidance

To detect this vulnerability, monitor outbound requests from your Crawl4AI instances, especially those targeting internal, loopback, or cloud-metadata addresses. Check for unusual DNS rebinding attempts or redirects in the robots.txt fetch logs. Disable check_robots_txt temporarily to see if it reduces unexpected outbound traffic.

Impact Analysis

This vulnerability allows unauthenticated attackers to bypass network restrictions and access internal services or cloud metadata. It can enable port scanning, service discovery, and potential data exfiltration by exploiting blind SSRF. Attackers may also use it to probe internal systems or bypass security controls in Docker environments.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data or systems, violating confidentiality requirements under GDPR and HIPAA. Organizations using affected versions may face compliance violations due to insufficient network access controls and potential data breaches.

Mitigation Strategies

Upgrade Crawl4AI to version 0.9.4 or later to patch the vulnerability. Disable check_robots_txt if not required. Restrict container network access to limit outbound connections. Enable authentication for the Crawl4AI service to prevent unauthenticated access.

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