Reported by 2 outlets
Anthropic's Opus 5 Shows Measurably Better Prompt-Injection Resistance
Why this score
- Breadth
- 1.00 / 2.0 · 2 sources
- Authority
- 1.00 / 2.0 · best outlet weight
- Severity
- 0.50 / 5.0 · CVSS + content signals
- Velocity
- 0.00 / 2.0 · updates in 48h
- Pickup speed
- 0.00 / 0.6 · time to second source
- Recency
- × 0.00 temporal multiplier
- Community
- + 0.00 / 1.5 · reddit signal
- Score
- 0.0 / 10 = base × recency + community
Timeline
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original reporting
Anthropic's Opus 5 Shows Measurably Better Prompt-Injection Resistance
schneier.com · 74d ago · August 1st, 2026
Bruce Schneier highlights Anthropic's chart showing Claude Opus 5 resisting prompt injection significantly better than prior models — timely given this week's disclosures of Claude models breaching real organizations during safety evaluations (covered Jul 31). The takeaway for defenders: model-level injection resistance is improving, but it is a control, not a cure — the evaluation-environment failures (exposed credentials, weak isolation) remain fully in the operator's court.
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update from cyberpress.org
Anthropic Claude Opus 5 Shows 98% Resistance to Indirect Prompt Injection Attacks
cyberpress.org · 64d ago · August 10th, 2026
Anthropic’s Claude Opus 5 has reduced successful indirect prompt injection attacks to 2% within 15 attempts, according to the company’s latest system card, marking the strongest result among models evaluated on the Gray Swan IPI benchmark. Indirect prompt injection is a critical risk for AI agents that read emails, browse websites, process documents, or invoke tools. An attacker can hide malicious instructions within otherwise legitimate content, attempting to get an AI agent to execute them. The potential impacts include sensitive data exfiltration, destructive actions, system compromise, and unauthorized financial activity. Put another way, it resisted 98% of attacks in that testing condition. The result improves significantly on Claude Opus 4.8 , where the attacker success probability reached 5.5% after 15 attempts. Opus 5 also reduced one-attempt attack success from 0.5% to 0.2%. Anthropic said the 28-scenario IPI benchmark was created with Gray Swan, the UK AI Security Institute, the US Center for AI Standards and Innovation, and other model developers. Anthropic described Opus 5 as the most robust model tested in the IPI evaluation. The company reported that the strongest non-Claude model, Muse Spark, had a 16.5% success rate within 15 attempts, more than eight t