Risk Letters

Exploited vulnerability

CVE-2026-63077

TLP:CLEAR

JetBrains TeamCity Deserialization of Untrusted Data Vulnerability

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

Facts

  • Vendor: JetBrains
  • Product: TeamCity
  • CVSS: 9.8
  • EPSS (probability of exploitation within 30 days): 93.6 %
  • On CISA's Known Exploited Vulnerabilities list since: 5 August 2026
  • First known exploitation: 5 August 2026
  • Used in ransomware campaigns (per CISA): Yes
  • CISA's deadline for US federal agencies: 8 August 2026
  • Weakness: CWE-502
  • First seen by Risk Letters: 5 August 2026

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Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD