Firefox 147 JS Exploitation

Anthropic internal Firefox 147 SpiderMonkey exploitation evaluation reported in the Claude Opus 4.8 system card.

4rows
full_working_exploit_rateprimary metric
2026-05-28sampled

Metadata

ID
firefox_147_js_exploitation
Category
Cybersecurity
Release
Unknown

Metrics

Full working exploit rate, Register control or full exploit rate

Latest Results

Provider-published system-card benchmark scores parsed from Anthropic's Claude Opus 4.8 capability evaluation tables. Rows are marked self-reported and should be interpreted as source claims unless independently reproduced.

Rank Subject Full working exploit rate Model Match Provenance Sampled
1 Claude Mythos Preview 70.8% Claude Mythos Preview
anthropic-claude-mythos-preview
 		Self-reported 2026-05-28
2 Claude Opus 4.8 8.8% Claude Opus 4.8
anthropic-claude-opus-4.8
 		Self-reported 2026-05-28
3 Claude Opus 4.7 1.2% Claude Opus 4.7
anthropic-claude-opus-4.7
 		Self-reported 2026-05-28
4 Claude Sonnet 4.6 0% Claude Sonnet 4.6
anthropic-claude-sonnet-4.6
 		Self-reported 2026-05-28