CVE-2020-15831
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 · uneditedJetBrains TeamCity before 2019.2.3 is vulnerable to reflected XSS in the administration UI.
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 · high confidenceReflected XSS vulnerability in JetBrains TeamCity administration UI allows attackers to inject malicious scripts through unsanitized user input that gets reflected back in server responses, potentially compromising administrator sessions.
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< 2019.2.3CVSS 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
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/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.
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Identify installed TeamCity versionLog into TeamCity web UI and navigate to Administration > Server Administration > Server Configuration to view the version number, or check the version.txt file in the TeamCity installation directoryAffected if Displayed version is less than 2019.2.3
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Confirm admin interface accessibilityAttempt to access the TeamCity administration console at the /admin/ endpoint path in the web interfaceAffected if Admin interface is reachable and accepts user input through URL parameters or form fields
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Verify user input reflection in responsesSubmit a test string with special characters (such as <script>alert(1)</script>) in admin URL parameters or form fields, then inspect the server response to see if the input is reflected back unsanitizedAffected if The submitted test string appears verbatim in the server response without encoding or sanitization
If TeamCity version is below 2019.2.3 and the admin interface is accessible with user input being reflected in responses without sanitization, the environment is affected by this reflected XSS vulnerability.
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.
From vendor data2019.2.3
Upgrade TeamCity to version 2019.2.3 or later to obtain the security patch; consider implementing Content Security Policy headers as additional defense-in-depth.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-15831 — 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-2020-15831 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
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- 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
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