Quoting Calif Research

Simon Willison's Blog 09/10/26, 12:56 AM News

security zero-click-exploit wechat ai-usage cybersecurity remote-code-execution

Summary

Calif Research demos WeWorm, a zero-click worm spreading through WeChat calls, with AI enabling rapid exploit development.

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# A quote from Calif Research Source: [https://simonwillison.net/2026/Sep/10/calif-research/](https://simonwillison.net/2026/Sep/10/calif-research/) 10th September 2026 > Today, we're releasing a demo of WeWorm, the first zero\-click worm to spread through WeChat calls across iOS and Android\. \[\.\.\.\] The victim does not need to answer the call, or interact with their phone at all\. Even if they do answer, they hear nothing, and the exploit still succeeds\. \[\.\.\.\] Working with AI, our team found the bug and wrote the first remote code execution \(RCE\) exploit in about two days\. Building the worm took one more week\. A worm at this scale used to be the kind of thing that took a larger team months\. AI can already do most of the work here\. Our team provided the judgment about what to target and how to test it safely\. —[Calif Research](https://calif.io/research/weworm),WeWorm

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