CVE-2026-25739: Indico affected by Cross-Site-Scripting via material uploads

Impact There is a Cross-Site-Scripting vulnerability when uploading certain file types as materials.

Patches You should to update to Indico 3.3.10 as soon as possible. See the docs for instructions on how to update.

Please be aware that to apply the fix itself updating is sufficient, but to benefit from the strict Content-Security-Policy we now apply by default for file downloads, you need to update your webserver config in case you use nginx with Indico's STATICFILEMETHOD set to xaccelredirect and add the following line to the .xsf/indico/ location block (you can consult the Indico setup documentation for the full configuration snippet):

nginx addheader Content-Security-Policy $upstreamhttpcontentsecuritypolicy;

Workarounds - Use your webserver config to apply a strict CSP for material download endpoints. - Only let trustworthy users create content (including material uploads, which speakers can typically do as well) on Indico.

For more information If you have any questions or comments about this advisory:

- Open a thread in our forum - Email us privately at indico-team@cern.ch