CVE-2026-63077
JetBrains TeamCity Deserialization of Untrusted Data Vulnerability
JetBrains TeamCity
In JetBrains TeamCity before 2026.1.3, 2025.11.7 unauthenticated remote code execution was possible via the agent polling protocol
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 5 August 2026. US federal agencies were required to remediate it by 8 August 2026. CISA records this vulnerability as known to be used in ransomware campaigns.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 94.9%, which is higher than 99.9% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2026-63077 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2026-63077.
What does CVE-2026-63077 affect?
CVE-2026-63077 affects JetBrains TeamCity. In JetBrains TeamCity before 2026.1.3, 2025.11.7 unauthenticated remote code execution was possible via the agent polling protocol
How severe is CVE-2026-63077?
CVE-2026-63077 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 94.9%, higher than 99.9% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 8 August 2026.
How should organisations respond to CVE-2026-63077?
Apply the vendor patch for JetBrains TeamCity as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.