Anubis vulnerable to possible XSS via redir parameter when using subrequest auth mode

### Summary When using subrequest authentication, Anubis did not perform validation of the redirect URL and redirects user to any URL scheme. While most modern browsers do not allow a redirect to `javascript:` URLs, it could still trigger dangerous behavior in some cases. `GET https://example.com/.within.website/?redir=javascript:alert()` responds with `Location: javascript:alert()`. ### Impact Anybody with a subrequest authentication seems affected. Using `javascript:` URLs will probably be blocked by most modern browsers, but using custom protocols for third-party applications might still trigger dangerous operations. ### Note This was originally reported by @mbiesiad against Weblate.

Source published

30 Oct 2025 17:08:12 UTC

Source modified

15 Nov 2025 03:11:17 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:H/SA:N

Publisher rating · MODERATE