Actively exploited in the wild
JetBrains TeamCity Deserialization of Untrusted Data Vulnerability
JetBrains - TeamCity · Listed in the CISA KEV since 2026-08-05. This indicates confirmed attacks in production environments.
Required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CVE-2026-63077
CriticalCVSS 9.8KEVExploitation Probability (EPSS)
Elevated risk60th percentile - higher than 60% of all known CVEs
Summary
In JetBrains TeamCity before versions 2026.1.3 and 2025.11.7, unauthenticated remote code execution is possible via the agent polling protocol.
Risk Assessment
An unauthenticated attacker can remotely execute arbitrary code on the TeamCity server, potentially leading to full system compromise.
Recommendation
Immediately update JetBrains TeamCity to version 2026.1.3 or later (or 2025.11.7 depending on the branch).
Original NVD description (English source)
In JetBrains TeamCity before 2026.1.3, 2025.11.7 unauthenticated remote code execution was possible via the agent polling protocol

