dbcve.org
TeamcityApplication · Jetbrains

CVE-2021-43193

CRITICAL · 9.8 CVSS v3.1 Published 2021-11-09
Fix available
A fix is available. Upgrade to 2021.1.2 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 2021.1.2, remote code execution via the agent push functionality is 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 · moderate confidence

A critical remote code execution vulnerability exists in JetBrains TeamCity's agent push functionality. Attackers can exploit this flaw without authentication to execute arbitrary code on affected TeamCity servers running versions prior to 2021.1.2.

MitigationUpgrade TeamCity to version 2021.1.2 or later to remediate this vulnerability. Given the critical CVSS score and RCE impact, prioritize this upgrade immediately and restrict network exposure of the TeamCity interface until patched.

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:< 2021.1.2

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 and version
    Locate the TeamCity installation directory and check the version file or build config. Common locations include the 'buildAgent' directory for agents and the main server directory for the TeamCity server. Look for a version.txt, build.txt, or check the server's about page in the web UI.
    Affected if The installed version is any release prior to 2021.1.2 (e.g., 2021.1.1, 2021.1, 2020.x series, or earlier)
  2. Verify agent push functionality is configured
    Check if the agent push feature is enabled on the TeamCity server. This is typically found in the TeamCity web interface under 'Agents' > 'Agent Push' settings, or by examining the internal configuration files in the TeamCity data directory related to agent registration.
    Affected if Agent push is enabled and the server allows unauthenticated or improperly authenticated agent registration requests
  3. Check server accessibility and network exposure
    Review network configuration to determine if the TeamCity web interface and agent communication ports (typically 9090 or configured agent ports) are exposed to untrusted networks. Examine firewall rules and reverse proxy settings.
    Affected if The TeamCity server is accessible from untrusted networks without proper network segmentation or authentication proxies
  4. Review agent configuration files
    Examine the 'buildAgent' directory configuration files, particularly any XML or properties files that control agent push registration behavior. Look for settings related to 'register' or 'authorization' in the agent configuration.
    Affected if Agent registration is configured to allow automatic or unauthenticated connections from agents

You are affected if your TeamCity installation is any version prior to 2021.1.2 AND the agent push functionality is enabled and accessible, allowing unauthenticated attackers to potentially execute arbitrary code on your server.

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 2021.1.2 or later
Fixed in 2021.1.2
Interim mitigation

Upgrade TeamCity to version 2021.1.2 or later to remediate this vulnerability. Given the critical CVSS score and RCE impact, prioritize this upgrade immediately and restrict network exposure of the TeamCity interface until patched.

Recommended fix High confidence

TeamCity 2021.1.2 or later (recommended: latest stable release)

  1. 1. Back up your TeamCity database and configuration files before starting the upgrade
  2. 2. Download the fixed TeamCity version (2021.1.2 or later) from the official JetBrains website
  3. 3. Stop the TeamCity server gracefully
  4. 4. Install the new TeamCity version, preserving your existing data directory
  5. 5. Start the TeamCity server
  6. 6. Verify that the server is running and the web interface is accessible
  7. 7. Confirm that the agent push functionality is working correctly
Caveat Review the release notes for any known migration or compatibility notes before upgrading

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

Fix this in Teamcity Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 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-2021-43193 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