CVE-2026-106218 is a sandbox-escape vulnerability in JetBrains TeamCity's Kotlin DSL, the scripting language TeamCity uses to define build configurations as code, that lets a Kotlin DSL script break out of its intended sandbox and run arbitrary code on the TeamCity server itself — a direct software-supply-chain risk, since TeamCity DSL scripts are typically stored and edited in the same version-control repositories as application source code and are evaluated automatically by the CI/CD server.
Vulnerability summary
10
Critical
0.3%
EPSS score (FIRST)
No
CISA KEV catalog
2026-10-06
Published
Vulnerability ID: CVE-2026-106218 · Source: NVD
Affected components
| Component | CPE | Version range |
|---|---|---|
| JetBrains TeamCity | cpe:2.3:a:jetbrains:teamcity:*:*:*:*:*:*:*:* | Before 2025.11.7 (fixed in 2025.11.7); 2026.1.1 through 2026.1.2 (fixed in 2026.1.3) |
What this means
CVE-2026-106218 (CWE-184, Incomplete List of Disallowed Inputs) affects JetBrains TeamCity, a widely used CI/CD server. NVD's description states: "In JetBrains TeamCity before 2026.1.3, 2025.11.7 kotlin DSL sandbox escape leading to RCE on the server was possible" (NVD).
TeamCity's Kotlin DSL feature lets teams define build configurations as Kotlin code committed to a repository, which TeamCity then compiles and evaluates inside a sandbox that is meant to restrict what the script can do on the server. CWE-184 (Incomplete List of Disallowed Inputs) indicates the sandbox's denylist-style restriction missed a way for DSL code to escape that sandbox and execute with the privileges of the TeamCity server process — i.e. a crafted build-configuration script, not a build step itself, is the attack vector.
NVD's own analysis gives it a Primary CVSS v3.1 base score of 10.0 (the maximum possible score), vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H — network-reachable, low attack complexity, no privileges or user interaction required, and critically, Scope Changed (S:C), reflecting that compromising the sandboxed DSL evaluator lets an attacker affect resources beyond the evaluator's own security scope (the TeamCity server as a whole). JetBrains' own CNA submission scores it lower, CVSS v3.1 8.8 with Scope Unchanged (S:U), vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H — the vendor's own rating both requires low privileges (PR:L, i.e. an account able to commit or edit a DSL-defined build configuration) and does not model the scope change NVD's Primary analysis applied. This 8.8-vs-10.0 gap is exactly a Scope Changed / privilege-requirement disagreement between the CNA and NVD's own re-analysis, and the GitHub Advisory Database mirrors the vendor's lower 8.8 figure at "high" severity (GitHub Advisory Database GHSA-p8v4-6cfg-7hh7).
The affected ranges, per NVD's CPE match data, are any version up to but not including 2025.11.7 on the 2025.11.x branch, and 2026.1.1 up to but not including 2026.1.3 on the 2026.1.x branch (NVD); JetBrains' own fixed-issues index for 2026.1.3 and 2025.11.7 is JavaScript-rendered and could not be fetched as static content for this advisory, so the affected/fixed version data above is drawn from NVD's CPE configuration rather than a WebFetch summary of that page.
As of 2026-10-30, FIRST scores the probability of exploitation at 0.00319 (24.7th percentile) (FIRST EPSS). CVE-2026-106218 is not currently listed in the CISA Known Exploited Vulnerabilities catalog (checked against the live KEV feed, catalog version 2026.10.30, 1766 entries).
Organizations running TeamCity in the affected ranges should upgrade to 2025.11.7 / 2026.1.3 or later and, in the interim, restrict who can author or modify Kotlin DSL build-configuration scripts — since whoever can commit a DSL script to a watched repository is the party positioned to trigger this sandbox escape against the CI/CD server that builds and signs the organization's software.
Evidence
- JetBrains TeamCity before 2026.1.3 and before 2025.11.7 allows a Kotlin DSL build-configuration script to escape its sandbox, leading to remote code execution on the server (CWE-184). — NVD
- NVD Primary CVSS v3.1 base score is 10.0, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (Scope Changed); JetBrains' own CNA submission scores it 8.8 with Scope Unchanged and PR:L, a materially different model of the same bug. — NVD
- GitHub Advisory Database mirrors the vendor's 8.8 CVSS v3.1 score at severity "high", CWE-184, and lists affected range as before 2026.1.3 / 2025.11.7. — GitHub Advisory Database
- EPSS score is 0.00319 (24.7th percentile) as of 2026-10-30; not present in the live CISA KEV feed (catalog version 2026.10.30, 1766 entries) checked by exact cveID match. — FIRST EPSS
