{"data":{"id":"d4a4072a-7cf3-49e1-9dba-fa8ecc3e69ba","title":"Behind the Scenes Hardening Firefox with Claude Mythos Preview","summary":"Mozilla used early access to Claude Mythos (an advanced AI model) to find and fix hundreds of security vulnerabilities in Firefox that had gone undetected for years. The AI became much more useful for this task once the model became more capable and Mozilla developed better techniques for controlling the AI, filtering out false reports, and combining multiple AI analyses together.","solution":"N/A -- no mitigation discussed in source.","labels":["industry","security"],"sourceUrl":"https://simonwillison.net/2026/May/7/firefox-claude-mythos/#atom-everything","publishedAt":"2026-05-07T17:56:25.000Z","cveId":null,"cweIds":null,"cvssScore":null,"cvssSeverity":null,"severity":"info","attackType":[],"issueType":"news","affectedPackages":null,"affectedVendors":["Anthropic"],"affectedVendorsRaw":["Anthropic","Claude Mythos","Mozilla","Firefox"],"classifierModel":"claude-haiku-4-5-20251001","classifierPromptVersion":"v3","cvssVector":null,"attackVector":null,"attackComplexity":null,"privilegesRequired":null,"userInteraction":null,"exploitMaturity":null,"epssScore":null,"patchAvailable":null,"disclosureDate":"2026-05-07T17:56:25.000Z","capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["integrity"],"aiComponentTargeted":"model","llmSpecific":true,"classifierConfidence":0.85,"researchCategory":null,"atlasIds":null}}