CVE-2026-119118 in Crawl4AI
Summary
by MITRE • 10/29/2026
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.
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Analysis
by VulDB Data Team • 10/29/2026
Crawl4AI versions prior to 0.9.5 suffer from a critical improper certificate validation vulnerability stemming from insecure Chromium launch configurations. The core technical flaw lies in the default initialization of the browser engine, which explicitly passes the --ignore-certificate-errors flag during startup. This configuration directive instructs the underlying Chromium process to bypass all SSL/TLS certificate verification checks, effectively disabling one of the primary mechanisms for establishing secure and authenticated connections over encrypted channels. By ignoring certificate errors such as expired certificates, self-signed certificates, or hostname mismatches, the application fails to validate the identity of remote servers it communicates with during web crawling operations. This creates a significant trust boundary violation where any network entity can present fraudulent credentials without triggering security warnings or connection failures within the crawler context.
The operational impact of this vulnerability is severe for organizations relying on Crawl4AI for data collection, as it enables man-in-the-middle attacks and DNS hijacking scenarios with ease. Attackers who control intermediate network infrastructure or possess the ability to manipulate Domain Name System resolutions can intercept traffic destined for target websites. Since the crawler does not validate server identities, these attackers can serve forged content that appears legitimate to the application while simultaneously capturing sensitive data transmitted during the crawl session. This includes reading cookies, authentication headers, and other potentially confidential information embedded in HTTP requests. The ability to inject malicious scripts or alter response payloads further compromises the integrity of the crawled data, leading to potential poisoning of downstream datasets used for analytics, machine learning training, or business intelligence.
Compounding this issue is the presence of a hard-coded --no-sandbox flag which overrides any user-configurable environment variables such as CRAWL4AI_CHROMIUM_SANDBOX intended to enable sandboxing protections. The Chromium sandbox is designed to isolate browser processes from the operating system and other applications, limiting the damage that can be done if an attacker exploits a vulnerability within the renderer process. By disabling this feature through hard-coded command-line arguments, Crawl4AI exposes itself to additional risks beyond just network interception. If combined with other potential vulnerabilities in the rendering engine or JavaScript execution environment, the lack of sandboxing could allow for arbitrary code execution on the host machine where the crawler is running. This significantly expands the attack surface from mere data theft to full system compromise under certain conditions.
From a classification perspective, this vulnerability aligns closely with CWE-295 Improper Certificate Validation and CWE-863 Incorrect Authorization Assertion regarding the failure to enforce security policies correctly. In terms of adversary tactics, it facilitates MITM attacks as described in the ATT&CK technique T1071 Application Layer Protocol for command and control or data exfiltration contexts where encrypted channels are spoofed. To mitigate these risks, users must upgrade immediately to version 0.9.5 or later which addresses these configuration defaults. For those unable to update instantly, it is imperative to manually override the launch arguments by ensuring that --ignore-certificate-errors is not passed and that sandboxing remains enabled through proper environment variable settings if supported by the specific deployment architecture. Additionally, implementing network-level controls such as mutual TLS authentication or strict certificate pinning at the infrastructure level can provide an additional layer of defense against interception attempts even when client-side validation is compromised.