GLM 5.3 built Firefox exploit chains without human input in under 48 hours
Epoch AI researchers report that GLM 5.3 autonomously built exploit chains against 6 Firefox versions by exploiting the gap between publicly visible security fixes and their delivery to users. Successful attacks cost roughly $1,000 in API fees each, with the fastest taking 12 hours. Mozilla patched a previously unknown sandbox vulnerability used in the attacks in Firefox 159.0; the researchers have not confirmed whether similar attacks work against that version.

Why it matters
The findings illustrate how publicly visible security fixes can guide autonomous exploit development during the interval before patches reach users, exposing a structural risk that faster updates alone cannot eliminate.











