Patch nowWhy this label: known ransomware use

CVE-2026-63077JetBrains TeamCity Deserialization of Untrusted Data Vulnerability

Product: JetBrains TeamCity
Added to CISA KEV: August 5, 2026
Deadline for US federal agencies: August 8, 2026
Known ransomware use: Yes, per CISA
EPSS, next 30 days: 94%, in the top 1% of scored CVEs (Oct 25, 2026)
Weakness: CWE-502

What CISA says

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

What CISA asks you to do

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.

Sources

Also exploited recently

Data from CISA's Known Exploited Vulnerabilities catalog (public domain) and FIRST EPSS, refreshed hourly. Rheono did not find or test this vulnerability; this page summarizes public sources.