# CVE-2026-100253: JetBrains TeamCity sandbox escape in versioned settings Kotlin DSL

Source: https://junglewise.ai/threats/cve-2026-100253-in-jetbrains-teamcity-before-2026-2-2026-1-4-2025-11-8-sandbox  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-30. Updated: 2026-09-30  
License: CC BY 4.0 with a link back

CVE-2026-100253 · Severity: high · CVSS 8.8 · Published 2026-09-30

JetBrains TeamCity is a continuous integration and deployment server used by development teams to automate software builds and testing. An attacker could exploit a sandbox escape vulnerability in the versioned settings Kotlin DSL feature to execute arbitrary code on the TeamCity server, potentially compromising the entire build pipeline and any systems it deploys to.

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

## Quick answers

**Is CVE-2026-100253 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100253 being exploited in the wild.

**How severe is CVE-2026-100253?** High severity, with a CVSS score of 8.8, published 30 September 2026.

**Which products and versions are affected?** Jetbrains TeamCity before 2026.2, 2026.1.4, 2025.11.8.

**Is there a fix for CVE-2026-100253?** 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-2026-100253 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-100253?** 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 sandbox escape vulnerability exists in TeamCity's versioned settings Kotlin DSL that allows code execution. The vulnerability affects the Kotlin DSL processing component and permits an attacker to break out of the intended sandbox restrictions, gaining arbitrary code execution on the server. The vulnerability has been patched in versions 2026.2, 2026.1.4, and 2025.11.8.

## Affected products

- JetBrains TeamCity before 2026.2, 2026.1.4, 2025.11.8

## Timeline

- 2026-09-30: disclosed

## 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)