# Epoch researchers used GLM 5.3 to exploit six Firefox releases > Source: > Published: 2026-10-30 01:26:03+00:00 # Epoch researchers used GLM 5.3 to exploit six Firefox releases **The file-reading attacks combined clues in published security fixes with an unpublished flaw; Mozilla patched that flaw in Firefox 159, though Epoch has not tested whether the update blocks the attack.** By [RuntimeWire Staff](https://runtimewire.com/author/runtimewire-staff) · Published Primary source: [Hacker News](https://epoch.ai/publications/open-weight-models-patch-gap) ## Why it matters The Firefox tests show that public security fixes can give an open-weight model enough information to build a working file-reading exploit before users receive the patch. Epoch's $1,000 estimate applies only after its harness was built, and Firefox 159's effectiveness against the full attack path remains unconfirmed. [Epoch AI researchers](https://epoch.ai/publications/open-weight-models-patch-gap?ref=runtimewire) used [Z.ai's](https://z.ai/?ref=runtimewire) open-weight [GLM 5.3](https://runtimewire.com/models/together/zai-org-glm-5.3-ab35037a1203d76c) model to build file-reading exploits against six Firefox releases, turning public security fixes into clues about vulnerabilities before those fixes reached users. The experiments show how quickly the "patch gap" can become a practical target: after building its test setup, Epoch estimated each successful attack cost about $1,000 in model API fees.… When you purchase through links in our articles, [we may earn a small commission](https://runtimewire.com/affiliate-monetization-standards). This doesn’t affect our editorial independence.