{"data":{"id":"74b7abf0-1571-40ad-a333-270eb171d377","title":"Claude Haiku 5.5","summary":"Anthropic released Claude Haiku 5.5, a fast, low-cost model priced at $0.10 per million input tokens and $0.50 per million output tokens up to 100,000 tokens, rising to $0.50/$2.50 beyond that. The author found it uses a tokenizer that consumes about 1.25x as many tokens as Haiku 4.5 on the same long prompt, and that it defaults to medium reasoning effort and cannot disable reasoning.","solution":"N/A -- no mitigation discussed in source.","labels":["industry","policy"],"sourceUrl":"https://simonwillison.net/2026/Oct/7/claude-haiku-5-5/","publishedAt":"2026-10-07T20:56:21.000Z","cveId":null,"cweIds":null,"cvssScore":null,"cvssSeverity":null,"severity":"info","attackType":[],"issueType":"news","affectedPackages":null,"affectedPackageNames":null,"affectedPackageRefs":null,"affectedVendors":["Anthropic","OpenAI"],"affectedVendorsRaw":["Claude Haiku 5.5","Claude Haiku 4.5","Claude Sonnet 5.5","GPT-6 Luna","llm-anthropic","Codex","Claude Token Counter"],"classifierModel":"claude-haiku-5-5","classifierPromptVersion":"v4","summaryPromptVersion":"v2","headline":null,"headlinePromptVersion":null,"cvssVector":null,"attackVector":null,"attackComplexity":null,"privilegesRequired":null,"userInteraction":null,"exploitMaturity":null,"epssScore":null,"epssCheckedAt":null,"kevDateAdded":null,"advisoryAliases":null,"affectedPackagesSource":null,"affectedPackagesCheckedAt":null,"patchAvailable":null,"disclosureDate":"2026-10-07T20:56:21.000Z","capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":null,"aiComponentTargeted":null,"llmSpecific":true,"classifierConfidence":0.95,"researchCategory":null,"atlasIds":null}}