Anthropic published an early-draft Cyber Jailbreak Severity framework, developed with Project Glasswing partners, to score cyber jailbreaks on capability gain, breadth, ease of weaponization and discoverability, mapped to five levels from CJS-0 to CJS-4. It also described Fable 5's cyber classifier tiers, which block prohibited and high-risk dual-use requests such as exploit development while allowing defensive work like patching and incident response.
Why it matters
A shared severity scale for safeguard bypasses is a precondition for proportionate government and industry responses like the June 2026 suspension.
Key facts
As stated in the sources, with where to find them.
- Severity bands: CJS-0 informational (0), CJS-1 low (1-3.5), CJS-2 medium (4-6.5), CJS-3 high (7-8.5), CJS-4 critical (9-10).CJS framework section
- Classifier tiers: prohibited use (blocked), high-risk dual use such as exploit development and privilege escalation (blocked), low-risk dual use (monitored, sometimes blocked), benign use (allowed).Classifier section
- Anthropic says Fable 5's safety margin was set larger than for other models, accepting more false positives.Classifier section
- Scoring axes: capability gain (0-4), breadth (0-2), ease of weaponization (0-2), discoverability (0-2).Cyber Jailbreak Severity section
Findings that cite this record
No tracked finding cites this record yet.
Key questions this bears on
- Is AI shifting the balance between finding and fixing vulnerabilities?Discovery is ahead. AI finds real vulnerabilities faster than they are fixed, and simple checks overstate how often AI patches work.
- Can AI agents defend and oversee systems on their own?Not yet. Agents are weak on realistic defensive benchmarks and monitors can be evaded; assistants help analysts who stay in charge.
- How are attackers using AI agents in real operations?Increasingly to run parts of intrusions: providers and vendors report agent-driven espionage, extortion and credential theft, and malware that queries LLMs.
Sources
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