GLM 5.3 built Firefox exploit chains in patch-gap tests
The tests show how an open-weight model can use visible fixes to attack Firefox users before patches reach them.
• In Epoch AI tests, GLM 5.3 built exploit chains against six Firefox versions using fixes visible before release.
• Successful attacks cost roughly $1,000 in API fees each, and the fastest took 12 hours.
• Mozilla patched a vulnerability used in the tests in Firefox 159.0, released October 27, 2026.
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October 30, 2026 26
