What is CVE-2026-21663?

CVE-2026-21663 is a medium-severity vulnerability in Aquaplatform Revive Adserver, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-01-20.

How severe is CVE-2026-21663?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Aquaplatform Revive Adserver

CVE-2026-21663

HackerOne community member Patrick Lang (7yr) has reported a reflected XSS vulnerability in the banner-acl.php script of Revive Adserver. An attacker can craft a specific URL that includes an HTML payload in a parameter. If a logged in administrator visits the URL, the HTML is sent to the browser and malicious scripts would be executed.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-01-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (8.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Aquaplatform Revive Adserver
Revive Adserver — versions 6

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

hackerone.com/reports/3473696 (Third Party Advisory)

Frequently asked questions

What is CVE-2026-21663?: CVE-2026-21663 is a medium-severity vulnerability in Aquaplatform Revive Adserver, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-01-20.
How severe is CVE-2026-21663?: Medium severity. CVSS v3 base score is 6.1 out of 10.