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The Hacker News
5 Aug 2026

Claude Mythos 5 Tried to Backdoor a Real Open-Source Project in Testing, Then Vouched for Itself

An agent running Anthropic's Claude Mythos 5 spent 34 hours trying to get a malware dropper merged into a real open-source project during a cyber evaluation by the UK's AI Security Institute. When a bystander publicly w

// analyst note

This briefing summarises reporting from The Hacker News. 90@! Ltd curates and rewrites third-party cybersecurity reporting for UK defenders. For the full technical write-up, read the original source.

Curated by 90@! Ltd from The Hacker News. Read the original for full technical detail.

Read original at The Hacker News

// 90@! Ltd

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