CVE-2026-63077
JetBrains TeamCity Deserialization of Untrusted Data Vulnerability
CVSS
9.8
Critical
EPSS
86.5%
p100
KEV
YES
Aug 5, 2026
Exploit Today
80
0-100
Published: Jul 27, 2026 · Last modified: Aug 6, 2026 · CWE-502
Product
JetBrains / TeamCity
Vulnerability
JetBrains TeamCity Deserialization of Untrusted Data Vulnerability
Added to KEV
Aug 5, 2026
Remediate by
Aug 8, 2026
Known ransomware use
No
Summary description
JetBrains TeamCity contains a deserialization of untrusted data vulnerability that could allow unauthenticated remote code execution via the agent polling protocol.
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.
Notes
https://blog.jetbrains.com/teamcity/2026/07/cve-2026-63077/; https://www.jetbrains.com/privacy-security/issues-fixed/ ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-63077
In JetBrains TeamCity before 2026.1.3, 2025.11.7 unauthenticated remote code execution was possible via the agent polling protocol