CVE-2021-37545
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 · uneditedIn JetBrains TeamCity before 2021.1.1, insufficient authentication checks for agent requests were made.
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 confidenceIn JetBrains TeamCity before 2021.1.1, the authentication mechanism for build agents connecting to the TeamCity server was insufficient, allowing unauthorized agents to potentially connect or impersonate legitimate build agents. This is a network-exploitable authentication bypass with high impact on the CI/CD pipeline integrity.
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< 2021.1CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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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Determine your TeamCity server versionAccess the TeamCity web UI and navigate to the Administration > Diagnostics > About page, or check the logs directory for version information in startup logsAffected if The version displayed is lower than 2021.1 (for example, 2021.0.x, 2020.x, or earlier)
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Identify configured build agentsIn TeamCity web UI, go to Administration > Agents > Agent Connections to list all registered build agents and their connection statusAffected if You have build agents configured and the server version is below 2021.1.1
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Review agent authentication settingsIn TeamCity web UI, navigate to Administration > Server Configuration > Agent Connections and verify the authentication settings for build agentsAffected if Agent authentication is enabled but the server version is below 2021.1.1
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Inspect server logs for unauthorized connection attemptsExamine TeamCity server logs in the logs directory (typically located at <TeamCity_HOME>/logs/) for entries containing 'agent' and 'authentication' or 'connection' warnings around the time of agent connectionsAffected if There are connection logs showing agents connecting without proper authentication validation or any anomalies in agent connection patterns
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Compare installed version to affected rangesIf you cannot access the web UI, check the TeamCity installation directory for a version file or examine the teamcity-server.log startup file for the version numberAffected if The identified version is any release before 2021.1.1
You are affected if your TeamCity server version is any release prior to 2021.1.1 and you have build agents configured to connect to the server.
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 data2021.1
Upgrade TeamCity to version 2021.1.1 or later to obtain the patched authentication validation for agent requests. Verify agent configurations and monitor for unauthorized connections.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-37545 — 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-2021-37545 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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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