CVE-2026-16889

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 45/100
Published: 2026-10-29 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity

CVSS Vector Breakdown

AV: Network
AC: Low
PR: High
UI: Passive
S: X
AT: None
VC: None
VI: None
VA: None

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.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
Apereo Foundation openEQUELLA 2019.1 < 2026.1

Bug Bounty Relevance

45 / 100
✓ Network accessible
✓ Low complexity

CVSS Score

4.8 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.32%
Raw Score 0.003150
Percentile 24.4%
Date 2026-10-29

Intelligence Sources

mitre ref →
nvd ref →