Security readout for executives and security teams
Plain-English summary
JetBrains TeamCity versions before 2020.2.3 had an argument injection flaw that could allow remote code execution. For executives, the concern is that a compromised CI/CD server can affect software delivery and build integrity. The bundle does not provide CVSS, attack prerequisites, or confirmed exploitation evidence.
Executive priority
Prioritize remediation for any production or internet-reachable TeamCity instance. CI/CD compromise can create downstream software supply-chain risk, so this should be handled as a high-priority infrastructure issue despite missing CVSS details.
Technical view
CVE-2021-31909 describes argument injection in JetBrains TeamCity before 2020.2.3, with potential remote code execution. The provided sources do not specify affected components, authentication requirements, exploit maturity, or detailed remediation beyond the fixed-version boundary implied by “before 2020.2.3.”
Likely exposure
Organizations running JetBrains TeamCity earlier than 2020.2.3 are potentially exposed. Exposure is more concerning where TeamCity is reachable by untrusted networks or handles sensitive build, release, or signing workflows. The source bundle does not confirm whether authentication is required.
Exploitation context
The bundle does not show CISA KEV listing or other cited evidence of active exploitation. Because the issue can lead to remote code execution on a CI/CD platform, security teams should treat unpatched instances as materially risky even without exploitation confirmation.
Researcher notes
Available evidence is sparse: no CVSS vector, CWE, affected CPEs, exploit details, or prerequisites are included. The central technical fact is argument injection enabling possible RCE in TeamCity before 2020.2.3. Avoid assuming exploitability conditions not present in the sources.
Mitigation direction
- Upgrade JetBrains TeamCity to 2020.2.3 or later.
- Review the JetBrains Q1 2021 security bulletin for vendor guidance.
- Prioritize instances exposed to the internet or shared networks.
- Restrict TeamCity access if immediate upgrading is delayed.
- Preserve logs before remediation if compromise is suspected.
Validation and detection
- Inventory all TeamCity instances and record installed versions.
- Flag any TeamCity version earlier than 2020.2.3.
- Confirm whether TeamCity is reachable from untrusted networks.
- Review TeamCity audit and build logs for unexpected activity.
- Verify the upgraded instance reports version 2020.2.3 or later.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
Execution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-31909 mapping review
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Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://blog.jetbrains.com/CVE reference · x_refsource_MISC
- https://blog.jetbrains.com/blog/2021/05/07/jetbrains-security-bulletin-q1-2021/CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.