What is CVE-2021-42080?

CVE-2021-42080 is a high-severity vulnerability in Osnexus Quantastor, classified under Cross-site Scripting. CVSS score: 7.4/10. Published 2023-07-10.

How severe is CVE-2021-42080?

High severity. CVSS v3 base score is 7.4 out of 10.

XSS in Osnexus Quantastor

CVE-2021-42080

An attacker is able to launch a Reflected XSS attack using a crafted URL. POC: Visit the following URL https://<IPADDRESS>:8153/qstorapi/echo?inputMessage=<img%20src=x%20onerror=alert(document.cookie)>

Vulnerability class: XSS (Cross-Site Scripting)

Published 2023-07-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.1th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Osnexus Quantastor — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

www.wbsec.nl/osnexus (technical-description, Third Party Advisory, third-party-advisory)
csirt.divd.nl/DIVD-2021-00020/ (third-party-advisory)
www.osnexus.com/products/software-defined-storage (Product, product)
csirt.divd.nl/CVE-2021-42080 (technical-description, Third Party Advisory, exploit, third-party-advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2021-42080?: CVE-2021-42080 is a high-severity vulnerability in Osnexus Quantastor, classified under Cross-site Scripting. CVSS score: 7.4/10. Published 2023-07-10.
How severe is CVE-2021-42080?: High severity. CVSS v3 base score is 7.4 out of 10.