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[ CVE-2026-63077 · Published 27 Jul 2026 ]

JetBrains TeamCity Deserialization of Untrusted Data Vulnerability

Exploited · CISA KEV CVSS 9.8 EPSS 90%No fix listed yet

[ Why it matters ]Priority signals

  • Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2026-08-05
  • Known to be used in ransomware campaigns
  • EPSS: 90% chance of exploitation in the next 30 days (higher than 100% of CVEs)
  • Critical severity: CVSS 9.8

[ Description ]Official description

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

CISA: JetBrains TeamCity contains a deserialization of untrusted data vulnerability that could allow unauthenticated remote code execution via the agent polling protocol.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 8 Aug 2026): 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.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References