Cyber Resilience

CVE-2021-42080

High

Published: 10 July 2023

Published
10 July 2023
Modified
22 September 2025
KEV Added
—
Patch
—
CVSS Score v3.1 7.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
EPSS Score 0.0018 39.3th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-42080 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Osnexus Quantastor. Its CVSS base score is 7.4 (High).

Operationally, ranked at the 39.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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)>

CWE(s)
CWE-79

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

osnexus
quantastor
≤ 6.0.0.355

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

SI-10 Information Input Validation
addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

SI-15 Information Output Filtering
addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

References