CVE-2026-52807

Gogs has DOM-based XSS via Milestone Name on New Issue Page

Published

2026-06-23

Modified

2026-07-21

EPSS percentile

39%

Aliases

GHSA-vcm5-gvmp-78mp

Sources

github-advisory

Summary

### 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](https://github.com/user-attachments/files/26508268/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.

Affected packages

Remediation: Upgrade to 0.14.3 or later.

References

• https://github.com/advisories/GHSA-vcm5-gvmp-78mp