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CVE-2026-16889medium4.8

Stored XSS via Pre-Login Notice Image Upload Serves Attacker HTML from Application Origin

Impact

openEQUELLA before 2026.1 allows stored cross-site scripting via pre-login notice image upload. A user with EDIT_SYSTEM_SETTINGS permission can upload an HTML file served as text/html. Unauthenticated exploitation is possible if the guest user or everyone has this permission.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

What to do

Update to vendor recommended versions

MON-CSIRT guidance

Affected packages

This source has no supported package-version data for matching. You can read the advisory here, but this record alone cannot power a dependency check.

Affected products

Vendor version evidence. Product records are separate from automatic dependency matching.

Apereo Foundation · MON-CSIRT

openEQUELLA

1 range
MON-CSIRT version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

2019.1 → before 2026.1

custom versions

unaffected

unknown

Other versions: unaffected

Original source 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.

Inside the record

Evidence available

Package identity · not supplied
Version evidence
Remediation guidance
Weakness classification
Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-16889

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-434 ↗

CWE-434 Unrestricted upload of file with dangerous type

MON-CSIRT

Related →
Contributing organizations · 2
MON-CSIRT

Assigning organization

2026-10-29
CISA-ADP

Additional data publisher

2026-10-29

What changed

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References

2 sources
github.com/openequella/openEQUELLA/security/advisories/GHSA-q2xv-rffq-mj5w
vendor-advisoryMON-CSIRT
openequella.github.io/guides/
productMON-CSIRT