CVE-2026-118008 in Firefox
Summary
by MITRE • 10/27/2026
Privilege escalation in the DOM: Navigation component. This vulnerability was fixed in Firefox 159.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/28/2026
The identified vulnerability represents a critical flaw within the Document Object Model implementation of Mozilla Firefox, specifically affecting the navigation component responsible for handling browser history and page transitions. As a privilege escalation issue, this defect allows an attacker to bypass intended security restrictions by leveraging improper state management or permission checks during DOM manipulation events associated with navigation actions. In modern web architectures, the DOM serves as the primary interface between JavaScript code running in a sandboxed environment and the underlying browser engine. When vulnerabilities exist within components that manage high-privilege operations such as navigating across origins or modifying session history, they can be exploited to break out of these sandboxes or elevate privileges from untrusted script execution to trusted chrome-level access.
The technical root cause likely stems from a logic error where the navigation component fails to adequately validate the context in which certain DOM methods are invoked. An attacker could craft a malicious webpage that triggers specific sequences of events, such as rapid history manipulation combined with cross-origin frame interactions or dynamic element injection. By exploiting race conditions or incomplete state resets during these transitions, the attacker may trick the browser into executing privileged functions under the guise of standard user interaction. This type of flaw is particularly dangerous because it often does not require complex exploitation techniques like buffer overflows but rather relies on subtle misinterpretations of security boundaries by the rendering engine.
From an operational impact perspective, successful exploitation could lead to full compromise of the user's browsing session and potentially the host system depending on the browser's sandboxing effectiveness. An attacker gaining chrome-level privileges can access sensitive data stored in local storage or cookies, inject malicious scripts into trusted pages, bypass content security policies, and interact with other open tabs without restriction. This effectively neutralizes many of the core isolation mechanisms designed to protect users from malicious websites. The impact is severe because it undermines trust in the browser as a secure execution environment for web applications that handle sensitive information such as banking details or corporate credentials.
This vulnerability aligns closely with CWE-269, which describes Improper Privilege Management, where software does not properly assign privileges to actors based on their authorization level. Furthermore, from an offensive security perspective, this behavior maps to MITRE ATT&CK techniques related to browser exploitation and privilege escalation within the client-side environment. Attackers often utilize such flaws as part of a broader campaign involving drive-by downloads or targeted phishing attacks where initial access is gained through social engineering but persistence and lateral movement are achieved via these deeper system compromises.
Mitigation strategies primarily involve applying the vendor-provided patch available in Firefox version 159, which addresses the underlying logic errors within the navigation component's DOM handling routines. Organizations should enforce automated update policies to ensure all client machines receive security patches promptly upon release. Additionally, implementing strict Content Security Policies can help mitigate potential downstream effects by restricting script execution sources and preventing unauthorized data exfiltration even if a sandbox escape occurs partially. Developers building web applications should also adhere to secure coding practices that minimize reliance on complex DOM manipulations during navigation events and validate all inputs before processing them through browser APIs.