<2> How Anthropic’s Claude Helped Mozilla to Improve Firefox’s Security
<3> Introduction
Mozilla’s Firefox is one of the most widely used web browsers, known for its security features and open-source codebase. However, even with its robust security measures, Firefox is not immune to bugs and vulnerabilities. Recently, Anthropic’s advanced artificial-intelligence model, Claude, discovered over 100 bugs in Firefox, including 14 high-severity ones, during a two-week testing period. This article will explore how Claude’s findings helped Mozilla improve Firefox’s security.
<3> The Testing Process
In January, Anthropic’s team submitted Claude Opus 4.6 to Mozilla for internal testing. The model was tasked with finding bugs in Firefox’s codebase. Within 20 minutes, Claude discovered its first Firefox browser bug, which was deemed serious by Mozilla’s developers. The team quickly wrote back, asking for more information and requesting a call to discuss the findings.
Over the next two weeks, Claude continued to scan Firefox’s codebase, discovering more than 100 bugs in total, including 14 high-severity ones. This is a significant number, considering that Firefox typically patches around 73 high-severity or critical bugs per year.
<3> The