CVE-2021-4406: Osnexus Quantastor

High severity, CVSS 7.2. EPSS: 1% chance of exploitation in the next 30 days.

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 inspect /tmp/ttttttddddssss it'll contain the ids of the root user.

Affected products

• Osnexus Quantastor: before 6.0.0.355 (fixed in 6.0.0.355)

Published 2023-07-10. Last modified 2026-06-17.