Firefox 158 Patches 77 Security Vulnerabilities
The latest browser update introduces a more granular CVE reporting policy for memory-safety bugs.
Updated on Oct. 16, 2026 in Cybersecurity
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Mozilla has released Firefox 158, which includes patches for 77 disclosed security vulnerabilities. The update is now available for all users, alongside a corresponding release for Firefox ESR 153.5.
Why it matters
This release marks a change in Mozilla's transparency policy as it begins assigning individual CVEs to memory-safety bugs rather than grouping them. This shift increases granular visibility into the specific security flaws addressed in each update cycle.
Mozilla addressed 77 unique security vulnerabilities in this release, shifting to a policy of individual CVE tracking for memory-safety errors. None of these vulnerabilities are currently identified as being under active exploitation.
The players
Mozilla
A non-profit organization that develops the open-source Firefox web browser and maintains Gecko, its rendering engine.
The details
Mozilla now publishes dedicated entries for each memory-safety vulnerability—bugs occurring when a program incorrectly handles computer memory, potentially allowing unauthorized data access—instead of aggregating them under one CVE. This granular approach provides researchers more specific data on how distinct code weaknesses are identified and patched. Users can trigger the update process by navigating to the Help menu within the browser application.
Timeline
October 13, 2026: Mozilla released Firefox 158 and Firefox ESR 153.5.
The Tech Race
Mozilla is currently updating its reporting standards to align with more granular tracking of memory-safety flaws through the Common Vulnerabilities and Exposures (CVE) system. This move reflects a broader industry trend toward increased transparency in browser security maintenance.
Desktop users should manually check their browser version via the Help menu to initiate the update process to version 158. The patch is also available for those maintaining the stable Firefox ESR 153.5 release channel.
The takeaway
Mozilla is increasing transparency by breaking out memory-safety bugs into distinct vulnerability entries. Users should monitor the official release notes for these individual CVE identifiers to track if specific memory-related patterns emerge in future browser builds.
Further reading
For broader trends in browser safety, see our latest coverage in Cybersecurity.
Source note: This article includes information reported by ESecurityPlanet.
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