dbcve.org
TeamcityApplication · Jetbrains

CVE-2021-31915

CRITICAL · 9.8 CVSS v3.1 Published 2021-05-11
Fix available
A fix is available. Upgrade to 2020.2.4 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
In JetBrains TeamCity before 2020.2.4, OS command injection leading to remote code execution was possible.

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 confidence

A critical OS command injection vulnerability in JetBrains TeamCity versions prior to 2020.2.4 allows unauthenticated attackers to execute arbitrary operating system commands on the hosting server, leading to complete remote code execution. The vulnerability is network-exploitable with low attack complexity, requiring no user interaction or special privileges.

MitigationUpgrade TeamCity to version 2020.2.4 or later. If immediate patching is not possible, restrict network access to TeamCity administrative interfaces and implement input validation on any exposed parameters.

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
TeamcityApplication
Affected:< 2020.2.4

CVSS 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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify TeamCity installation
    Search for TeamCity installation directories (common paths: /opt/teamcity, C:\TeamCity, /usr/local/TeamCity) or running processes (teamcity-server, TeamCity). Check if the TeamCity web interface is accessible on common ports (8111).
    Affected if TeamCity software is present in the environment
  2. Determine installed TeamCity version
    Access the TeamCity web interface and navigate to Administration > Server Administration > Server Information, or check the version file in the installation directory (typically <teamcity_home>/buildAgent or the About page at /about.html). Alternatively, check server logs in <teamcity_home>/logs for startup messages showing version.
    Affected if Version cannot be determined or is less than 2020.2.4
  3. Verify version against affected range
    Compare the identified version number to 2020.2.4. TeamCity versions follow a major.minor.patch format (e.g., 2020.2.3, 2021.1.1).
    Affected if Installed version is any build prior to 2020.2.4 (e.g., 2020.2.3, 2020.1.x, 2019.x)
  4. Check network exposure of TeamCity interfaces
    Determine if TeamCity admin interfaces are accessible from untrusted networks. Review firewall rules, reverse proxy configurations, or cloud security groups allowing access to port 8111 (default) from outside your trusted network.
    Affected if TeamCity web interface is exposed to the internet or untrusted networks without authentication barriers

The environment is affected if TeamCity is installed and the installed version is any build earlier than 2020.2.4.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 2020.2.4 or later
Fixed in 2020.2.4
Interim mitigation

Upgrade TeamCity to version 2020.2.4 or later. If immediate patching is not possible, restrict network access to TeamCity administrative interfaces and implement input validation on any exposed parameters.

Recommended fix High confidence

TeamCity 2020.2.4 or later

  1. 1. Back up your TeamCity data directory, database, and configuration files before upgrading
  2. 2. Download TeamCity 2020.2.4 or a later stable version from the official JetBrains website (www.jetbrains.com/teamcity/download/)
  3. 3. Stop the TeamCity server service
  4. 4. Install the new version using the standard TeamCity upgrade procedure - either by running the installer or replacing the TeamCity installation directory
  5. 5. Start the TeamCity server and verify all services are running correctly
  6. 6. Test that the command injection vulnerability is no longer present by verifying normal TeamCity operations work as expected
Caveat Review the TeamCity 2020.2.4 release notes for any breaking changes or migration requirements specific to your configuration

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Teamcity Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,440
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,504.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-31915 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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