CVE-2026-55790 Craft CMS: DOM XSS via GitHub issue title in CraftSupport widget

Craft CMS is a content management system CMS. In versions 5.0.0-RC1 through 5.9.22 and 4.0.0-RC1 through 4.17.15, an attacker with only a GitHub account can plant a JavaScript payload in a craftcms/cms issue title. When a Craft admin uses the CraftSupport widget’s "Give feedback" screen and types...

CVE-2026-55790

Summary of CVE-2026-55790 (Craft CMS) : This is a DOM-based cross-site scripting flaw in Craft CMS. Versions affected are 5.0.0-RC1–5.9.22 and 4.0.0-RC1–4.17.15. An attacker with only a GitHub account can insert a JavaScript payload into a craftcms/cms issue title. When a Craft admin uses the Cra...