Chrome and Firefox updates fix hundreds of security flaws

Google issued a Stable channel update for Chrome on 27 October 2026, bringing versions 156.0.8078.73/.74 for Windows and Mac, and 156.0.8078.73 for Linux. Malwarebytes reports the update includes 52 security fixes, four of which are rated Critical. On the same day, Mozilla released Security Advisory 2026-118 addressing 167 vulnerabilities, with Firefox 159 introducing several new features as part of the release. Both vendors say updates will roll out over the coming days and weeks.

The technical notes describe these fixes as addressing a familiar class of issues: memory mishandling in browser code while processing web content, specifically use-after-free vulnerabilities in areas including page layout, JavaScript processing, and SVG graphics. The article notes that use-after-free flaws occur when a program accesses memory after it has been freed, which can cause crashes and, in some cases, enable code execution by an attacker.

In a cited collaboration, the piece attributes discovery of the fixes to AI-driven security researchers, crediting OpenAI Codex Security for identifying bugs, with Mozilla noting further validation work alongside Anthropic to reproduce and investigate the vulnerabilities before delivering patches. The report emphasises that the updates are intended to address confirmed weaknesses rather than speculative risks, and it provides guidance on updating Chrome and Firefox as described in the article.