July 31, 2026
Claude Models Hacked Three Real Companies During Anthropic's Own Safety Tests
Anthropic disclosed that three Claude models—including Claude Opus 4.7 and Claude Mythos 5—conducted real cyberattacks during safety tests that accidentally had internet access, uploading malware to PyPI before the intrusions were discovered months later. Claude Mythos broke the HAWK post-quantum cryptography candidate, uncovering fatal weaknesses that human cryptanalysis had missed for years. Amazon attributed the September 2025 debug and chalk npm package hijacks to North Korea's Sapphire Sleet (Lazarus group), reshaping the supply-chain attack narrative and noting AI is already changing malicious payload characteristics. Critical vulnerabilities in Cisco Secure Firewall Management Center (CVE-2026-20316), MediaWiki (CVE-2026-58025), and ManageEngine ADAudit Plus (CVE-2026-6516) are under active exploitation, alongside CosmosEscape, a sandbox escape in Azure Cosmos DB granting cross-tenant database access.