PatchTheCVECVE-2021-4406: An authenticated attacker is able to create alerts that trigger a stored XSS attack. POC * go to the ale
CVE-2021-4406 is a critical-severity flaw (CVSS 9.1) affecting quantastor. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
An authenticated attacker is able to create alerts that trigger a stored XSS attack. POC * go to the alert manager * open the ITSM tab * add a webhook with the URL/service token value ' -h && id | tee /tmp/ttttttddddssss #' (whitespaces are tab characters) * click add * click apply * create a test alert * The test alert will run the command “id | tee /tmp/ttttttddddssss” as root. * after the test alert i
Why this priority
- Critical severity
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.1 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | High |
| User interaction | None |
| EPSS exploit chance | 1.0% (top 38%) |
| CISA exploited list | No |
| Weakness | CWE-77 |
| Published | 2023-07-10 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
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-2021-4406?
quantastor: upgrade to 6.0.0.355. Exact commands for each OS are on this page.
Is CVE-2021-4406 being exploited?
CVE-2021-4406 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-2021-4406 affect?
CVE-2021-4406 affects quantastor. Severity is critical (CVSS 9.1). An authenticated attacker is able to create alerts that trigger a stored XSS attack. POC * go to the alert manager * open the ITSM tab * add a webhook with the URL/service token value ' -h && id | tee /tmp/ttttttddddssss #'
How urgent is CVE-2021-4406?
Priority 47/100. Critical severity
Related CVEs
- 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-2021-42080 HIGH 7.4 UPGRADE An attacker is able to launch a Reflected XSS attack using a crafted URL. POC: Visit the following URL https
- CVE-2021-42079 MEDIUM 6.2 UPGRADE An authenticated administrator is able to prepare an alert that is able to execute an SSRF attack