A critical SQL injection flaw in Ghost CMS (CVE-2026-26980, CVSS 9.4) has been actively exploited since May 7 to compromise over 700 public websites. The vulnerability was discovered by Anthropic using Claude and patched in February in version 6.19.1. A lot of sites are still running unpatched versions. Here's what attackers are doing with it. The flaw lets anyone pull a Ghost site's admin API key without authenticating. With that key they can call the admin API directly and modify every published article on the site in bulk. Attackers have been using this to inject malicious JavaScript loaders at the bottom of articles across hundreds of sites. When a real visitor lands on one of these compromised pages, the injected code serves them a fake CAPTCHA prompt. It looks like a standard human verification check. The prompt tells them to copy a command and paste it into the Windows Run dialog to prove they are human. Running that command installs malware. The compromised sites include universities, AI companies, SaaS platforms, fintech companies, and security research firms. The legitimacy of those domains is exactly what makes the attack effective. If you run Ghost CMS, here is what to do right now. Update to version 6.19.1 or later, rotate your admin API key and all credentials, open your published articles and check the bottom of the content for any script tags you did not add, and review your server access logs for unusual activity since May 7. If you find evidence of compromise, notify users who visited during that window. For anyone visiting websites generally, if a CAPTCHA ever asks you to copy something and paste it into a Run dialog or terminal, that is malware. Close the tab.