CVE-2021-42083
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThe vulnerability exists in the Alert Manager's ITSM webhook functionality, where the URL/service token field fails to sanitize input properly. An authenticated attacker can inject shell commands (like '&& id | tee /tmp/...') that execute with root privileges when a test alert is triggered. The official description incorrectly states 'stored XSS' - the POC clearly demonstrates OS command injection.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 6.0.0.355CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify the installed Quantastor versionRun the command to display the Quantastor version, typically via the web UI system information page or CLI command like 'qs_version' or checking /opt/quantastor/etc/version file if accessible.Affected if The installed version is any build prior to 6.0.0.355.
-
Locate the Alert Manager ITSM webhook configurationNavigate to Alert Manager settings in the Quantastor web interface or examine the configuration files under /opt/quantastor/etc/ or similar paths where alert configurations are stored.Affected if The ITSM webhook feature exists in the environment.
-
Inspect the webhook URL field for injection payloadsView the configured webhook URL in Alert Manager settings. Look for shell metacharacters such as &&, ;, |, >, <, backticks, or $() in the URL field.Affected if The URL field contains any shell command operators or suspicious character sequences that were not intentionally configured by an administrator.
-
Inspect the service token field for injection payloadsView the configured service token in the ITSM webhook settings. Examine for shell metacharacters similar to those checked in the URL field.Affected if The service token field contains any shell command operators or suspicious character sequences.
-
Check for unexpected files in /tmpOn the Quantastor system, list files in /tmp directory using 'ls -la /tmp' and look for files created by command injection such as those containing output from injected commands like 'id' or other reconnaissance tools.Affected if Unexpected files exist in /tmp that correspond to the injected command pattern shown in the POC (e.g., files containing user/group information).
A defender is affected if running any Osnexus Quantastor version below 6.0.0.355 with the Alert Manager ITSM webhook feature enabled and the URL or service token fields contain unsanitized shell metacharacters that could have been injected by an authenticated attacker.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped6.0.0.355
Implement strict input validation and escaping on all webhook configuration fields. Use allowlists for permitted characters and avoid passing user input directly to shell execution functions. Consider running alert services with minimal privileges rather than root.
Quantastor 6.0.0.355 or later
- Upgrade Quantastor to version 6.0.0.355 or later to resolve the vulnerability
- Verify the upgrade was successful by checking the Quantastor version number
- Test that alert webhooks no longer execute arbitrary commands by creating a test alert with a benign payload
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42083 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-42083 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data