CVE-2026-16889

Medium

Description

In openEQUELLA before 2026.1, the pre-login notice image upload endpoint (PUT /api/preloginnotice/image/{name}) does not validate the type of uploaded files and serves them with a Content-Type derived from the supplied filename. A user holding the EDIT_SYSTEM_SETTINGS permission can upload an HTML file that is then served as text/html from the openEQUELLA origin, resulting in stored cross-site scripting. Unauthenticated exploitation is possible where EDIT_SYSTEM_SETTINGS has been granted to the guest user or everyone.

SeverityMedium

CVSS4.8

Exploit probability—

ProductopenEQUELLA

PublishedOct 29, 2026

First seenNov 4, 2026

Weakness typeCWE-434Unrestricted upload of dangerous file type

How to fix

Update

Apereo Foundation openEQUELLA2026.1 or later

Vendor advisories

github.com/openequella/openEQUELLA/security/advisories/GHSA-q2xv-rffq-mj5w

Affected products

Product	Affected versions	Fixed in
Apereo Foundation openEQUELLA	2019.1 ≤ v < 2026.1	2026.1

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.