Applied Cybernetics Group
Threat intel → detection pipeline
Friday, September 18, 2026
Data as of 13:09 UTC

JetBrains TeamCity Deserialization of Untrusted Data Vulnerability

Added to KEV
2026-08-05
Federal due date
2026-08-08
Vendor
JetBrains
Product
TeamCity
EPSS
99.7th percentile (score 0.865, as of 2026-09-16)
NVD CVSS v3.1
9.8 (CRITICAL)
Ransomware use
Unknown
Upstream
https://nvd.nist.gov/vuln/detail/CVE-2026-63077

CISA short 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.

NVD description

In JetBrains TeamCity before 2026.1.3, 2025.11.7 unauthenticated remote code execution was possible via the agent polling protocol

EPSS percentile is the FIRST.org exploit-probability ranking as of the date noted above; it moves daily. CVSS reflects NVD's analysis at time of publication.