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CVE-2026-63077

JetBrains — JetBrains TeamCity Deserialization of Untrusted Data Vulnerability

JetBrains · CWE-502 — Deserialization of untrusted data · in CISA KEV since 2026-08-05

ExigentCISA federal deadline · Overdue by 2 monthsRansomwareCISA KEVActively Exploited
95

EVRS 95 of 100 Immediate

Out-of-Band / Urgent Remediation

Rank 12 of 2,960 tracked

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Why it scores 95

Evidence available: 6 of 7 signals

Listed in the CISA KEV catalog, and associated with known ransomware campaigns.

  • CISA KEVApplied
  • RansomwareApplied
  • Vendor exploitationDid not apply
  • EPSSApplied
  • Microsoft Exploitability IndexNot applicable
  • Pre-patch disclosureNo data
  • KEV recencyApplied
  • CVSSApplied

The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data

Fix

Patch or fixed version identified

CISA required action

Fixed in

teamcity: update to 2025.11.7 or later | teamcity: update to 2026.1.3 or later

Affected versions

  • teamcity< 2025.11.7>= 2026.1 < 2026.1.3

Remediation

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.

Fixed versions from NVD.

Evidence

Each value with its source
MeasureValueSource
CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. 9.8 NVD
FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. 0.896 (99.79th pctl) FIRST EPSS
Actively exploitedWhether a source of record has confirmed attacks using it in the wild. Confirmed CISA KEV
Ransomware campaign useWhether CISA has seen ransomware operators use it. Known CISA KEV
CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. 2026-08-08 · CISA federal deadline · Overdue by 2 months CISA KEV
Public exploit moduleA module existing is not the same as active exploitation. Public module exists Metasploit
EUVD cross-referenceENISA's record: CVSS 9.8 (v3.1), assigned by JetBrains. Listed ENISA EUVD

Description

NVD

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

What CISA says to do

Public module

Metasploit lists a public excellent-rank module for this CVE: JetBrains TeamCity Agent Polling Unauthenticated Remote Code Execution (multi/http/jetbrains_teamcity_rce_cve_2026_63077). A module existing is not the same as active exploitation; see metasploit.com.