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PatchSiren cyber security CVE debrief

CVE-2023-42793 JetBrains CVE debrief

CVE-2023-42793 affects JetBrains TeamCity and is described as an authentication bypass vulnerability. CISA added it to the Known Exploited Vulnerabilities catalog on 2023-10-04, indicating active exploitation concerns and known ransomware campaign use. For defenders, this is a high-priority CI/CD exposure because TeamCity often sits close to build systems, credentials, and release workflows.

Vendor
JetBrains
Product
TeamCity
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2023-10-04
Original CVE updated
2023-10-04
Advisory published
2023-10-04
Advisory updated
2023-10-04

Who should care

Organizations running JetBrains TeamCity, especially on-premises deployments; CI/CD platform owners; security operations teams; and incident response teams tracking externally exposed build infrastructure.

Technical summary

The vulnerability is characterized by authentication bypass in JetBrains TeamCity. The supplied official records do not include exploit mechanics, but CISA’s KEV entry shows it was considered actively exploited and associated with known ransomware campaign use. The practical risk is unauthorized access to TeamCity instances and the systems or secrets they can reach.

Defensive priority

Critical. CISA KEV inclusion, same-day publication and KEV addition, and known ransomware campaign use all point to urgent remediation.

Recommended defensive actions

  • Apply vendor mitigations or update to the fixed TeamCity release referenced by JetBrains.
  • If mitigations are not available or cannot be applied quickly, discontinue use of the affected product until it can be secured.
  • Prioritize Internet-facing TeamCity instances and verify whether any deployments remain vulnerable.
  • Review TeamCity access logs, authentication events, and recent configuration or credential changes for signs of unauthorized activity.
  • Follow incident response procedures if the environment shows indicators of compromise or unexpected job, user, or token changes.

Evidence notes

CISA KEV lists JetBrains TeamCity Authentication Bypass Vulnerability, adds it on 2023-10-04, and marks known ransomware campaign use as Known. The KEV notes point to JetBrains’ vendor advisory and the NVD record. The CVE and timeline supplied here show publication and modification on 2023-10-04, which is the relevant issue date context.

Official resources

Publicly disclosed and added to CISA KEV on 2023-10-04; treat as actively exploited based on official KEV status.