JetBrains TeamCity: Remote code execution via whitelist bypass in build messages
Summary
JetBrains TeamCity, a self-hosted CI/CD build server, contains a deserialization flaw (CWE-502) that allows remote code execution. The vulnerability is caused by a whitelist bypass in the build messages protocol. Sources disagree on the attack complexity (NVD mirror shows high, the CNA record shows low), so the CVSS score of 9.8 should be verified against the NVD record.
Affected
- TeamCity before 2026.2
- TeamCity 2026.1 through 2026.1.4 (per Vulners range; check the vendor advisory for exact ranges)
- TeamCity before 2025.11.8 (per Vulners range; check the vendor advisory for exact ranges)
Fixed in
- TeamCity 2026.2
- TeamCity 2026.1.4
- TeamCity 2025.11.8
Workaround
Unknown.
Exploitation
- No evidence of exploitation in the wild found.
- CISA SSVC: Exploitation none, Automatable no.
- Not listed in KEV.
- No public exploit available according to VulDB.
Our recommendation
- Inventory all TeamCity servers and their versions and note internet-facing instances.
- Upgrade to TeamCity 2026.2, 2026.1.4 or 2025.11.8 as soon as possible.
- Restrict access to TeamCity server and agent endpoints to internal networks or VPN where possible.
- Review logs and rotate build and deployment credentials if a server was exposed before patching.
- Also upgrade to at least 2025.11.7 or 2026.1.3 to address the related CVE-2026-63077.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- JetBrains: Fixed security issues www.jetbrains.com
- NVD record data mirror (OpenCVE) app.opencve.io
- VulDB entry 420700 vuldb.com
- Vulners CVE-2026-111094 vulners.com
- Strix CVE-2026-111094 www.strix.ai
- SafeSecurity: CVE-2026-63077 (related TeamCity RCE) safe.security
- WhiteHat: TeamCity build RCE whitehat.eu
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 30 Oct 2026, 17:47.
Original description (NVD)
In JetBrains TeamCity before 2026.2, 2026.1.4, 2025.11.8 remote code execution via a whitelist bypass in the build messages protocol was possible
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.