CVE-2021-42080: An attacker is able to launch a Reflected XSS attack using a crafted URL. POC: Visit the following URL https

Q: How do I fix CVE-2021-42080?

quantastor: upgrade to 6.0.0.355. Exact commands for each OS are on this page.

Q: Is CVE-2021-42080 being exploited?

CVE-2021-42080 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-42080 affect?

CVE-2021-42080 affects quantastor. Severity is high (CVSS 7.4). An attacker is able to launch a Reflected XSS attack using a crafted URL. POC: Visit the following URL https:// :8153/qstorapi/echo?inputMessage=

Routine

HIGH 7.4UPGRADE

CVE-2021-42080 is a high-severity flaw (CVSS 7.4) affecting quantastor. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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)>

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.4 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Weakness	CWE-79
Published	2023-07-10
Last modified	2026-06-17

Publisher (CNA): Dutch Institute for Vulnerability Disclosure · Vendor: osnexus

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-07-10 16:15 UTCPublished CVE record published
2026-06-17 04:09 UTCUpdated Record last modified

osnexus quantastor UPGRADE

Affected: < 6.0.0.355

Fixed in: 6.0.0.355

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy quantastor || rpm -q quantastor || quantastor --version

2. UPGRADE to 6.0.0.355 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade quantastor

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade quantastor

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-42080?

quantastor: upgrade to 6.0.0.355. Exact commands for each OS are on this page.

Is CVE-2021-42080 being exploited?

CVE-2021-42080 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-42080 affect?

CVE-2021-42080 affects quantastor. Severity is high (CVSS 7.4). 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)>

How urgent is CVE-2021-42080?

Priority 39/100. High severity

Related CVEs

CVE-2021-4406 CRITICAL 9.1 UPGRADE An authenticated attacker is able to create alerts that trigger a stored XSS attack. POC * go to the ale
CVE-2021-42083 HIGH 8.7 UPGRADE An authenticated attacker is able to create alerts that trigger a stored XSS attack. POC * go to the ale
CVE-2021-42082 HIGH 7.8 UPGRADE Local users are able to execute scripts under root privileges. POC On the local host run the following comma
CVE-2021-42081 CRITICAL 9.1 UPGRADE An authenticated administrator is allowed to remotely execute arbitrary shell commands via the API. POC http:
CVE-2021-42079 MEDIUM 6.2 UPGRADE An authenticated administrator is able to prepare an alert that is able to execute an SSRF attack

References

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