Deserialization of Untrusted Data in TeamCity - CVE-2026-63077
Published: July 27, 2026 / Updated: August 27, 2026
Vulnerability identifier: #VU140627
CSH Severity: Critical
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63077
CWE-ID: CWE-502
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to deserialization of untrusted data in the agent polling protocol when processing agent polling requests. A remote attacker can send specially crafted protocol data to execute arbitrary code.
Affected software
TeamCity
How to mitigate CVE-2026-63077
Install security update from vendor's website.
TeamCity - addressed in versions 2025.11.7, 2026.1.3
Links to Public Exploits and PoC-codes
- Exploit #12979 - JetBrains TeamCity Agent Polling Unauthenticated Remote Code Execution (August 27, 2026)
- Exploit #12919 - CVE-2026-63077 (CVE-2026-63077 — Unauthenticated Remote Code Execution in JetBrains TeamCity via agent polling protocol deserialization. CVSS 9.8 CRITICAL. Mass exploitation tool with interactive shell, multi-threading, and real-time result logging.) (August 14, 2026)