TeamCity is a widely used CI/CD platform; an RCE sandbox escape can lead to code execution, secrets theft, and supply-chain/enterprise disruption.
CVE-2026-100253
TeamCity Kotlin DSL sandbox escape allows remote code execution
Is CVE-2026-100253 being exploited?
Not confirmed. CVE-2026-100253 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.
How severe is CVE-2026-100253?
CVE-2026-100253 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-100253?
Yes. A fix has been recorded for CVE-2026-100253. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-100253 affect?
CVE-2026-100253 affects JetBrains TeamCity < 2026.2, JetBrains TeamCity 2026.1 < 2026.1.4, JetBrains TeamCity 2025.11 < 2025.11.8. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-100253?
Upgrade to fixed TeamCity versions, restrict CI access, rotate secrets, and review logs
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution on TeamCity via versioned settings Kotlin DSL sandbox escape; attackers can run arbitrary code, access secrets, and pivot.
Immediate action required
- affected< 2026.2, 2026.1.4, 2025.11.8
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.