How severe is CVE-2021-42083?

CVE-2021-42083 has a CVSS 3.x base score of 8.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-42083 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-42083?

CVE-2021-42083 affects Osnexus Quantastor. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-42083?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-42083 published?

CVE-2021-42083 was published on 2023-07-10 and last updated on 2026-06-17.

CVE-2021-42083

CVE-2021-42083 is a high-severity vulnerability in Osnexus Quantastor with a CVSS 3.x base score of 8.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: High (CVSS 3.x base score 8.7)
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Osnexus Quantastor
Published: 2023-07-10
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-42083?: 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.
How severe is CVE-2021-42083?: CVE-2021-42083 has a CVSS 3.x base score of 8.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-42083 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-42083?: CVE-2021-42083 affects Osnexus Quantastor. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-42083?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-42083 published?: CVE-2021-42083 was published on 2023-07-10 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:osnexus:quantastor:*:*:*:*:*:*:*:*

More vulnerabilities in Osnexus Quantastor

CVE-2021-4406 — Critical (CVSS 9.1): An authenticated attacker is able to create alerts that trigger a stored XSS attack. POC * go to the alert…
CVE-2021-42081 — Critical (CVSS 9.1): An authenticated administrator is allowed to remotely execute arbitrary shell commands via the…
CVE-2021-42082 — High (CVSS 7.8): Local users are able to execute scripts under root privileges. POC On the local host run the following command: curl…
CVE-2021-42080 — High (CVSS 7.4): An attacker is able to launch a Reflected XSS attack using a crafted URL. POC: Visit the following…
CVE-2021-42079 — Medium (CVSS 6.2): An authenticated administrator is able to prepare an alert that is able to execute an SSRF attack. This is exclusively…
CVE-2017-9979 — Medium (CVSS 6.1): On the OSNEXUS QuantaStor v4 virtual appliance before 4.3.1, if the REST call invoked does not exist, an error will be…

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