GHSA-vcm5-gvmp-78mp Gogs has DOM-based XSS via Milestone Name on New Issue Page

• Go gogs.io/gogs: < 0.14.3 → fixed in 0.14.3

Summary The fix for GHSA-vgjm-2cpf-4g7c (DOM-based XSS via milestone selection) was only applied to `templates/repo/issue/view_content.tmpl` but not to `templates/repo/issue/new_form.tmpl`. An attacker can store an HTML/JavaScript payload in a milestone name, and when any user opens the New Issue page and interacts with the milestone dropdown, the payload executes in their browser via Semantic UI's `preserveHTML` behavior. Details GHSA-vgjm-2cpf-4g7c was patched by adding `| Sanitize` (bluemonday HTML tag stripping) to milestone name rendering in `view_content.tmpl`. However, the same milestone dropdown exists in `new_form.tmpl` and was not patched. In `new_form.tmpl`, milestone names are rendered with Go's default auto-escaping (`{{.Name}}`), which converts ``). Semantic UI 2.4.2's dropdown component has `preserveHTML: true` as the default setting. When a user selects a dropdown item, the internal `set.text()` method calls jQuery's `.html()` with the item's text content. This re-parses the decoded text as HTML, creating the injected element and triggering the JavaScript event handler. PoC poc.zip Please extract the uploaded compressed file before proceeding 1. docker compose up --build Impact • Stored DOM XSS: Any user with write access to a repository can create a malicious milestone. Any other user who visits the New Issue page and interacts with the milestone dropdown will have arbitrary JavaScript executed in their browser session. • Session hijacking: The attacker can steal session cookies, perform actions as the victim, or escalate privileges.