WeChat worm could pwn a friend before they even answered the call
With more than 1.4 billion monthly active users, WeChat is among the most popular apps in the world. According to researchers at Calif, its VoIP stack contained a memory corruption bug that could enable a trusted contact to take control of a user's account simply by calling them.Calif called the flaw WeWorm, describing it as the first zero-click worm capable of spreading through WeChat calls on both iOS and Android. REG AD googletag.cmd.push(function() { googletag.display('labrador/thereg/article/desktop/b'); }); Calif released a demo of the vulnerability in action this week, and although Tencent has pushed fixes to address the attack on August 21, the team that found it is still withholding key details.
- ▪With more than 1.4 billion monthly active users, WeChat is among the most popular apps in the world.
- ▪According to researchers at Calif, its VoIP stack contained a memory corruption bug that could enable a trusted contact to take control of a user's account simply by calling them.Calif called the flaw WeWorm, describing it as the first zero
- ▪REG AD googletag.cmd.push(function() { googletag.display('labrador/thereg/article/desktop/b'); }); Calif released a demo of the vulnerability in action this week, and although Tencent has pushed fixes to address the attack on August 21, the
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Story provenance
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Record
| Original publisher | theregister |
| Canonical URL | https://www.theregister.com/security/2026/09/09/wechat-worm-could-pwn-a-friend-before-they-even-answered-the-call/5295234 |
| Publication time | Wed, 09 Sep 2026 14:45:00 +0200 |
| Retrieval time | 2026-09-09T13:02:44.831Z |
| Last seen | 2026-09-09T13:02:44.831Z |
| Headline source | Publisher (no WeSearch rewrite) |
| Excerpt source | publisher body |
| Excerpt method | First ~120 words (~800 chars) of extracted publisher body, fair-use limited. |
| Summary | WeSearch · cerebras-chat (WeSearch summarizer) |
| Summary source text | contentText |
| Citation coverage | Summary is a WeSearch-generated derivative; primary citation is the original publisher URL. |
| Cluster | None |
| Cluster logic | Not yet clustered, or no peer story found in the clustering window. |
| Ranking reason | Story pages are not engagement-ranked. Hub feeds use recency, with optional source-diversified chronological ordering (cap consecutive stories per source). No personalized ranking. |
| Publisher visit | Yes — open original |
| Substitutes article? | No — link-out required for full text |
Rights status (four layers)
WeSearch handling by dimension
| Indexing | May the item be indexed (stored, ranked, made findable)? | Allowed |
| Snippet | May a short excerpt of the publisher's text be shown? | Allowed |
| AI summary | May WeSearch generate its own short summary of the article? | Limited |
| Retrieval / RAG | May the content be exposed for third-party retrieval-augmented generation? | Not asserted |
| Model training | May the content be used to train AI models? | Not asserted |
| Commercial reuse | May the content be reused commercially? | Not permitted |
Basis: Derived from the published RSS/Atom feed. Contact: [email protected]. Reviewed: 2026-07-24.
Opening excerpt (first ~120 words) tap to expand
(function() { let windowUrl = window.location.href; windowUrl = windowUrl.substring(windowUrl.indexOf('?') + 1); let messageElement = document.querySelector('.shareableMessage'); if (windowUrl && windowUrl.includes('code') && windowUrl.includes('expires')) { messageElement.style.display = 'block'; } })(); Security WeChat worm could pwn a friend before they even answered the call Calif says AI helped turn a VoIP memory bug into cross-platform RCE before Tencent shut it down Connor Jones Connor Jones Cybersecurity reporter Published wed 9 Sep 2026 // 13:45 UTC READ MORE Microsoft closes the book on Publisher and unplugs Project Online 42 minutes ago Security boffin claims airport group left API keys in client-side JavaScript for four years 1 hour ago Virgin Media offloads email services to…
Excerpt limited to ~120 words for fair-use compliance. The full article is at theregister.