RCE in a widely used CI server (TeamCity); can enable code/pipeline tampering, credential theft and supply-chain impact across organizations.
CVE-2026-65906
Remote code execution via Kotlin DSL sandbox escape in JetBrains TeamCity.
Is CVE-2026-65906 being exploited?
Not confirmed. CVE-2026-65906 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. EPSS currently estimates a 0.54% probability of exploitation in the next 30 days.
How severe is CVE-2026-65906?
CVE-2026-65906 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-2026-65906?
Yes. A fix has been recorded for CVE-2026-65906. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-65906 affect?
CVE-2026-65906 affects JetBrains TeamCity (versions prior to 2026.1.2 and 2025.11.6). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-65906?
Upgrade TeamCity to 2026.1.2 or 2025.11.6+, restrict access and review DSL scripts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Arbitrary code execution on TeamCity server via Kotlin DSL sandbox escape, enabling pipeline tampering, data exfiltration, or credential compromise.
Immediate action required
- affected< 2026.1.2, 2025.11.6
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.