CVE-2023-22798 in adblock-lists
Summary
by MITRE • 02/09/2023
Prior to commit 51867e0d15a6d7f80d5b714fd0e9976b9c160bb0, https://github.com/brave/adblock-lists removed redirect interceptors on some websites like Facebook in which the redirect interceptor may have been there for security purposes. This could potentially cause open redirects on these websites. Brave's redirect interceptor removal feature is known as "debouncing" and is intended to remove unnecessary redirects that track users across the web.
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Analysis
by VulDB Data Team • 10/03/2025
The vulnerability described in CVE-2023-22798 represents a critical security regression in the Brave browser's adblock list management system. This issue emerged from a specific code change that altered how Brave handles redirect interceptors on certain websites, particularly those with security-sensitive redirect mechanisms. The problem stems from the removal of redirect interception capabilities that were previously implemented to prevent tracking and maintain user privacy. The affected commit 51867e0d15a6d7f80d5b714fd0e9976b9c160bb0 introduced a change that inadvertently stripped away security measures designed to block malicious redirects while preserving legitimate tracking mechanisms. This modification specifically targeted websites like Facebook where redirect interceptors served as essential security controls, fundamentally altering the browser's approach to handling web navigation.
The technical flaw manifests through the removal of Brave's "debouncing" functionality, which was originally designed to eliminate unnecessary redirects that track users across the web. This feature operates by identifying and blocking redirects that do not serve legitimate purposes, thereby reducing tracking exposure. However, the implementation flaw resulted in the removal of redirect interceptors on security-critical websites where such interceptors were essential for preventing open redirect vulnerabilities. The vulnerability creates a path for malicious actors to exploit open redirect conditions, potentially leading to phishing attacks, credential theft, or other malicious activities. This represents a direct violation of security principles where legitimate security controls are removed in favor of privacy-focused features without proper consideration of the security implications on specific website domains. The flaw essentially transforms a privacy-enhancing feature into a security risk by removing protective mechanisms that were specifically designed to prevent malicious redirect exploitation.
The operational impact of this vulnerability extends beyond simple privacy concerns to encompass significant security risks for users interacting with affected websites. When redirect interceptors are removed from platforms like Facebook, users become vulnerable to open redirect attacks that could be exploited by threat actors to redirect them to malicious sites. This vulnerability directly aligns with attack patterns described in the attack tactic of initial access and the technique of open redirect, where attackers manipulate web applications to redirect users to harmful destinations. The security implications are particularly severe given that Facebook and similar platforms often implement redirect mechanisms for legitimate security purposes such as authentication flows, session management, and cross-site request forgery protection. Users may unknowingly be exposed to malicious redirects during normal browsing activities, potentially leading to account compromise or data exfiltration. The vulnerability demonstrates a dangerous trade-off between privacy and security features, where the removal of tracking prevention mechanisms inadvertently creates new attack vectors.
The mitigation strategies for this vulnerability require immediate attention from both browser developers and users. Brave browser developers must implement a more granular approach to redirect interception that preserves security controls while maintaining privacy benefits. This involves distinguishing between tracking redirects that should be blocked and security redirects that must be preserved. The solution should incorporate website-specific policies or whitelisting mechanisms that ensure security-critical redirects remain functional while still blocking malicious tracking redirects. From a user perspective, the immediate mitigation involves keeping the browser updated to versions that address this specific regression, as well as being vigilant about suspicious redirects when browsing affected platforms. Organizations should review their security policies to ensure that browser configurations properly account for this vulnerability, particularly in environments where users may be exposed to potentially compromised websites. This vulnerability highlights the importance of maintaining security controls even when implementing privacy-focused features, as demonstrated by the common weakness pattern identified in CWE-601, which addresses open redirect vulnerabilities in web applications. The fix should incorporate proper risk assessment frameworks that evaluate the security implications of privacy-enhancing features on a per-website basis.