A later review finds 16-21% of top patches semantically wrong.
Week of Feb 2–8, 2026
What changed in what we know
Anthropic reports multi-attempt rates in a system card.
Multi-attempt figures in Anthropic's system card are far higher than single-attempt rates.
New findings
Attacks & incidents
VirusTotal analyzed more than 3,016 OpenClaw skill packages and reports hundreds with malicious behavior, including data exfiltration, backdoors, malware droppers such as Atomic Stealer, and persistent instruction files that manipulate the agent. One publisher accounted for 314 malicious skills; VirusTotal added native scanning of skill packages.
Defense & research
A systematization-of-knowledge paper by organizers and competitors analyzes AIxCC's design, the seven finalist architectures and results beyond the scoreboard. It reports that system stability and accuracy penalties decided rankings, that LLM-based systems found vulnerabilities a fuzzing baseline missed, and that among patches passing all automatic validation, manual review found semantic errors in 38-46% from baseline agents; the top two systems had 83.8% and 79.2% competition-scored patch accuracy.
Anthropic's Claude Opus 4.6 system card reports prompt injection attack success separately for tool use (Gray Swan's ART benchmark), coding and computer use (Gray Swan's Shade adaptive attacker), and browser use (an internal Best-of-N attacker), with and without extra safeguards and across different attempt budgets. For Opus 4.6, results range from 0% in coding to 85.7% in computer use with 200 attempts and no safeguards (78.6% with extended thinking). Anthropic notes that, unlike earlier Claude models, extended thinking increased ART attack success for this model.
Anthropic's Frontier Red Team reports that Claude Opus 4.6, run in a VM with standard tools but no custom harness, found and validated more than 500 high-severity vulnerabilities in open-source software, focusing on memory corruption that can be confirmed with sanitizers. Every bug was validated before reporting, initially by Anthropic researchers who also wrote patches and later with external researchers; examples include Ghostscript, OpenSC and CGIF.