# CVE-2026-65906: JetBrains TeamCity remote code execution via Kotlin DSL sandbox escape

Source: https://junglewise.ai/threats/cve-2026-65906-jetbrains-teamcity-remote-code-execution-via-kotlin-dsl-sandbox  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-23. Updated: 2026-07-23  
License: CC BY 4.0 with a link back

CVE-2026-65906 · Severity: high · CVSS 8.8 · Published 2026-07-23

JetBrains TeamCity, a platform used by software teams to automate building and testing code, contained a vulnerability that allowed users to bypass security restrictions. An attacker with basic access could escape the restricted environment used for configuration scripts to run unauthorized code on the server. This could lead to a full takeover of the build system, potentially exposing sensitive source code or allowing the injection of malicious code into software releases.

Technologies: [Jetbrains TeamCity](https://junglewise.ai/threats/technologies/teamcity). Vendors: [Jetbrains](https://junglewise.ai/threats/vendors/jetbrains).

## Quick answers

**Is CVE-2026-65906 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-65906 being exploited in the wild.

**How severe is CVE-2026-65906?** High severity, with a CVSS score of 8.8, published 23 July 2026.

**Which products and versions are affected?** Jetbrains TeamCity before 2026.1.2, 2025.11.6.

**Is there a fix for CVE-2026-65906?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-65906 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-65906?** Check whether you run Jetbrains TeamCity at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A code injection vulnerability (CWE-94) exists in JetBrains TeamCity due to an improper sandbox implementation for Kotlin DSL (Domain Specific Language) configurations. An authenticated attacker with permissions to modify project configurations can craft a malicious Kotlin DSL script that escapes the intended execution sandbox. This allows for arbitrary code execution on the TeamCity server with the privileges of the service account. The vulnerability is fixed in versions 2026.1.2 and 2025.11.6.

## Affected products

- JetBrains TeamCity before 2026.1.2, 2025.11.6

## Timeline

- 2026-07-23: disclosed
- 2026-07-23: advisory

## References

- [https://www.jetbrains.com/privacy-security/issues-fixed/](https://www.jetbrains.com/privacy-security/issues-fixed/)

## Related threats

- [JetBrains TeamCity stored XSS in classic build log](https://junglewise.ai/threats/cve-2026-111096-in-jetbrains-teamcity-before-2026-2-2026-1-4-2025-11-8-stored)
- [JetBrains TeamCity stored XSS in project overview](https://junglewise.ai/threats/cve-2026-111095-in-jetbrains-teamcity-before-2026-2-2026-1-4-2025-11-8-stored)
- [JetBrains TeamCity remote code execution in build messages protocol](https://junglewise.ai/threats/cve-2026-111094-in-jetbrains-teamcity-before-2026-2-2026-1-4-2025-11-8-remote)
- [JetBrains TeamCity Git submodule URL validation bypass](https://junglewise.ai/threats/cve-2026-106219-in-jetbrains-teamcity-before-2026-2-1-missing-validation-of-git)
- [JetBrains TeamCity Kotlin DSL sandbox escape RCE](https://junglewise.ai/threats/cve-2026-106218-in-jetbrains-teamcity-before-2026-1-3-2025-11-7-kotlin-dsl)