# Firefox 159 Addresses 167 Security Vulnerabilities and Sandbox Escapes Mozilla releases Firefox 159 featuring critical security patches and new AI-assisted monitoring tools. - **Source:** [PCWorld](https://www.pcworld.com) - **Published:** 2026-10-28 - **Topic:** [Software & Engineering](https://brifing.si/c/engineering) - **Original article:** - **On Brifing:** https://brifing.si/s/cedac66b-2e7c-4397-9c25-2449e8c9b231 ## Comprehensive Security Patch Deployment Mozilla has officially released Firefox 159 across all major platforms, including Windows, macOS, Linux, and Android. This update addresses 167 distinct security vulnerabilities identified within the browser architecture. Among these, 65 flaws were reported by external security researchers, highlighting the ongoing collaborative effort required to maintain browser integrity and user safety. ## Critical Risk Assessment Breakdown The security advisory classifies 108 vulnerabilities as high risk, 52 as medium risk, and seven as low risk. Notably, 97 of these are use-after-free vulnerabilities, which could potentially facilitate malicious code injection. Furthermore, 13 specific vulnerabilities were identified that could allow attackers to successfully escape the browser's sandbox environment, posing significant threats. ## External Researcher Contributions External security researchers played a pivotal role in identifying these flaws, with Amy Burnett from OpenAI contributing seven individual reports. This high volume of external reporting underscores the complexity of modern browser security. Mozilla continues to rely on these independent audits to identify deep-seated issues that internal testing might otherwise overlook. ## New Sidebar Password Integration Firefox 159 introduces a new password management tool directly accessible within the browser sidebar. This feature is enabled by default for all users, regardless of whether they actively save passwords within the browser. This change aims to streamline credential management, though it represents a shift in default browser interface behavior for users. ## AI-Assisted Website Monitoring The update includes a new AI-based Smart Window feature designed to monitor websites for specific changes, such as new blog posts or price fluctuations. This functionality is currently being rolled out gradually to the user base. It represents Mozilla's strategic move toward integrating AI-driven automation tools directly into the core browsing experience. ## Extended Support Release Updates Mozilla has simultaneously updated its Extended Support Release (ESR) versions, specifically 153.6.0 and 115.44.0. These versions address 145 and 80 vulnerabilities respectively, ensuring security for legacy systems. These specific builds remain available for Windows 7, 8.1, and older macOS versions until March 2027, providing critical protection for users on older operating systems. ## Future Release Roadmap Following this release, the development team has already scheduled the next major iteration, Firefox 160, for November 10th. This rapid release cycle is essential for maintaining the security posture of the browser. Users should anticipate continued refinements to both the AI-assisted features and the underlying security architecture in the upcoming version. ## Impact on Browser Integrity The high number of sandbox escape patches in Firefox 159 demonstrates the persistent challenge of isolating web content from the host operating system. By addressing these vulnerabilities, Mozilla reinforces the browser's defense-in-depth strategy. Continuous updates remain the primary mechanism for preventing exploitation of memory-related flaws in modern, complex web browser environments. ## Sources covering this story - https://www.pcworld.com/article/3271386/firefox-159-fixes-167-security-flaws-including-13-sandbox-escapes.html — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._