Crawl4AI: Improper certificate validation via hard-coded Chromium flags
Summary
Crawl4AI launches Chromium with --ignore-certificate-errors, so the browser accepts any TLS certificate, and the hard-coded --no-sandbox flag overrides the sandbox setting. A network attacker who can intercept traffic or control DNS for a crawled host can serve forged content to the crawler and read cookies and headers that the crawl sends. The crawled content can then feed downstream systems such as RAG or LLM pipelines. The attack requires a man-in-the-middle or DNS-control position on the crawler's network path.
Affected
- Crawl4AI versions before 0.9.5 (Python library and Docker API server)
- The exact first affected version is unknown.
Fixed in
- Crawl4AI 0.9.5 (released 2026-10-14)
Workaround
- No complete workaround is known.
- Keep the crawler on a trusted network path and trusted DNS resolvers.
- Library users: set ignore_https_errors explicitly to False and verify that the setting is honoured (not independently verified).
Exploitation
- CISA SSVC lists exploitation as 'poc' (proof of concept); the advisory includes reproduction steps.
- No exploitation in the wild is known. The vulnerability is not listed in CISA KEV.
- EPSS: 0.19 % (percentile 8).
Our recommendation
- Inventory all Crawl4AI installations (pip packages and Docker images) and identify versions below 0.9.5.
- Upgrade to 0.9.5 or later, starting with internet-facing Docker API instances.
- Until upgraded, run crawlers only on trusted networks and do not let crawled content feed sensitive systems unchecked.
- Review the other Docker-server advisories fixed in 0.9.5, which may have higher priority.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- GitHub Security Advisory GHSA-j2qh-f73r-mg3q github.com
- VulnCheck advisory www.vulncheck.com
- CVE record mirror (cve.threatint.com) cve.threatint.com
- VulDB entry vuldb.com
- Strix CVE summary www.strix.ai
- Crawl4AI changelog github.com
- GitHub issue #2437 (TLS default discussion) github.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 13:04.
Original description (NVD)
Crawl4AI before 0.9.5 contains an improper certificate validation vulnerability that allows network attackers to intercept crawls because Chromium always launches with --ignore-certificate-errors. Man-in-the-middle or DNS-controlling attackers can serve forged content to the crawler and read cookies and headers sent, while hard-coded --no-sandbox also overrides CRAWL4AI_CHROMIUM_SANDBOX.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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