Coder: Stored HTML injection via unescaped ApplicationName and LogoURL appearance settings

Summary

The ApplicationName and LogoURL appearance settings were rendered into HTML output without sufficient escaping which let a highly privileged Owner-role user inject HTML into the Coder dashboard and SMTP notification emails.

Note: Exploitation requires the Owner role which already holds full administrative control of the deployment so practical impact is limited.

Impact

An Owner-role user could store HTML markup in the ApplicationName or LogoURL appearance settings that later rendered in the dashboard and in SMTP notification emails which results in stored HTML injection against other users of the deployment. Exploitation requires the highly privileged Owner role.

Patches

The fix escapes the ApplicationName and LogoURL appearance values in HTML output before rendering.

The fix was backported to all supported release lines:

Workarounds

Restrict the Owner role to trusted administrators.

References

• Fix: #25804

Credits

We'd like to thank Anthropic's Security Team (ANT-2026-22453) for independently disclosing this issue!