JetBrains IDE and TeamCity Critical Vulnerabilities
JetBrains Patches Critical Flaws in IDEs, TeamCity CI/CD Platform
CVE Identifiers
Full Report
Executive Summary
On August 5, 2026, JetBrains released a series of security patches addressing multiple critical and high-severity vulnerabilities across its product portfolio. The flaws impact the widely used TeamCity CI/CD platform and IntelliJ-based Integrated Development Environments (IDEs). These vulnerabilities represent a profound software supply chain risk, as they could allow threat actors to gain remote code execution, access sensitive files and credentials, and achieve a full compromise of an organization's software development infrastructure. Given that these tools are central to modern development workflows and often hold highly privileged credentials, immediate application of the provided patches is essential for all users.
Vulnerability Details
The security updates address several dangerous flaws. The most significant include:
CVE-2026-65907 (Critical): A remote code execution (RCE) vulnerability in TeamCity's Git Version Control System (VCS) Roots. This flaw could allow an attacker to execute arbitrary code on the TeamCity server, giving them control over build processes and access to all secrets managed by the server.
CVE-2026-65906 (High): A sandbox escape vulnerability in TeamCity's Kotlin DSL. This also leads to code execution on the TeamCity server, allowing an attacker who can influence build scripts to break out and compromise the underlying host.
CVE-2026-49366 (High): A command injection vulnerability in IntelliJ-based IDEs via filename completion. An attacker could craft a malicious filename that, when handled by the IDE's autocompletion feature, executes arbitrary commands on the developer's workstation.
CVE-2026-64814 (High): An unauthorized file access vulnerability during remote development sessions in IntelliJ-based IDEs. This could allow an attacker to read sensitive files from the developer's machine.
CVE-2026-64813 (High): An unauthorized setting modification vulnerability in IntelliJ-based IDEs, which could be used to weaken security settings or reconfigure the IDE for malicious purposes.
Other patched flaws include a stored XSS (CVE-2026-59794) and an arbitrary file access flaw in the Perforce integration (CVE-2026-59793).
Affected Systems
- JetBrains TeamCity: All versions prior to the patched releases are affected by CVE-2026-65907 and CVE-2026-65906.
- JetBrains IntelliJ-based IDEs: Includes IntelliJ IDEA, WebStorm, PyCharm, GoLand, and others. Specific version information is available in the JetBrains security advisories.
Exploitation Status
At the time of disclosure, JetBrains has not reported any evidence of active exploitation in the wild. However, vulnerabilities in developer tools, especially CI/CD platforms like TeamCity, are highly sought after by advanced threat actors for supply chain attacks. The public disclosure of these flaws makes it highly likely that exploitation attempts will begin shortly.
Impact Assessment
The potential impact of these vulnerabilities is critical. A compromise of a TeamCity server or a developer's IDE can be a 'keys to the kingdom' event.
- Software Supply Chain Compromise: An attacker could inject malicious code into an organization's software products before they are built and shipped to customers. This is a classic supply chain attack, similar to the SolarWinds incident.
- Credential and Source Code Theft: Attackers could steal source code, API keys, database credentials, and other secrets stored in the CI/CD environment or on developer machines.
- Pivot to Production Environments: With access to deployment credentials, an attacker could pivot from the development environment to compromise production cloud infrastructure and applications.
- Espionage and Sabotage: Nation-state actors could use this access for long-term espionage, while ransomware groups could use it to disrupt development and deploy ransomware across the organization.
Cyber Observables — Hunting Hints
- TeamCity: Monitor TeamCity server logs for unusual Git operations or errors related to VCS roots. Look for unexpected processes spawned by the TeamCity server process (e.g., shells, network utilities). Audit build logs for suspicious commands or scripts being executed by the Kotlin DSL.
- IntelliJ IDEs: On developer workstations, monitor for IDE processes (e.g.,
idea.exe,pycharm.exe) spawning unexpected child processes likecmd.exe,powershell.exe, orbash. This could indicate command injection from CVE-2026-49366. - Network: Monitor for anomalous outbound network connections from the TeamCity server or developer workstations to unknown IP addresses.
Detection Methods
- Vulnerability Scanning: Use authenticated scans to identify vulnerable versions of TeamCity and JetBrains IDEs across your server and workstation fleets.
- Log Analysis: Centralize and analyze logs from TeamCity servers. Create alerts for builds that fail in unusual ways or for administrative actions that are not tied to a known change request.
- Endpoint Detection and Response (EDR): EDR is crucial for detecting post-exploitation activity on both the TeamCity server and developer endpoints. Look for the MITRE ATT&CK techniques associated with command injection and sandbox escapes, such as
T1059 - Command and Scripting Interpreter.
Remediation Steps
- Update Immediately: The only effective remediation is to update all affected JetBrains products to the latest patched versions. Organizations should treat this with the highest priority.
- Restrict Access: As a compensating control, ensure that TeamCity servers are not exposed to the public internet. Access should be restricted to trusted IP ranges or require a VPN with multi-factor authentication.
- Credential Rotation: As a precautionary measure, consider rotating all secrets and credentials stored in TeamCity and those accessible to developers whose IDEs were vulnerable. This includes source code repository tokens, cloud provider keys, and artifact repository credentials.
Timeline of Events
MITRE ATT&CK Mitigations
The most critical mitigation is to immediately apply the security patches provided by JetBrains for all affected IDEs and TeamCity instances.
Mapped D3FEND Techniques:
Restrict network access to TeamCity servers. They should not be exposed to the public internet and should only be accessible from trusted internal networks or via a secure VPN.
Mapped D3FEND Techniques:
Run TeamCity build agents in ephemeral, isolated environments (e.g., containers) with minimal privileges and no persistent access to credentials to limit the impact of a build compromise.
Mapped D3FEND Techniques:
Use short-lived, single-purpose credentials for CI/CD pipelines instead of long-lived static secrets to reduce the value of a compromised TeamCity server.
Mapped D3FEND Techniques:
D3FEND Defensive Countermeasures
Given the critical nature of these vulnerabilities (e.g., CVE-2026-65907 RCE in TeamCity) and their position in the software supply chain, immediate patching is non-negotiable. Organizations must treat the JetBrains advisories as an emergency change request. Use asset management systems to identify all TeamCity servers and developer workstations with IntelliJ-based IDEs. Deploy the patches immediately, prioritizing internet-facing TeamCity servers first, then internal servers, and finally developer IDEs. Failure to patch leaves the core of the software development lifecycle open to complete takeover.
Beyond patching, hardening the configuration of TeamCity is crucial. Ensure that the server is not running with excessive privileges. Critically, the TeamCity server's management interface should never be exposed to the public internet. It should be firewalled off and accessible only via a secure VPN with MFA. Within TeamCity, enforce the principle of least privilege for build configurations. Each build job should only have access to the specific secrets it requires, using short-lived tokens where possible. This prevents a compromise in one build project from immediately escalating to a full compromise of all secrets stored on the server.
To detect potential exploitation of flaws like CVE-2026-49366 (command injection), EDR and process monitoring are essential. On both TeamCity servers and developer workstations, monitor the java.exe process (which runs the JetBrains products) for suspicious child processes. The IDE or CI/CD server should not be spawning shells (cmd.exe, bash), scripting interpreters (powershell.exe), or network utilities (curl, wget). Create high-severity alerts for these process chains. This behavioral detection can catch exploitation attempts even if the exact payload is unknown, providing a critical signal that an attacker is trying to break out of the application sandbox.
Timeline of Events
JetBrains releases security updates for multiple critical and high-severity vulnerabilities.
Sources & References
Article Author
Jason Gomes
• Cybersecurity PractitionerCybersecurity professional with over 10 years of specialized experience in security operations, threat intelligence, incident response, and security automation. Expertise spans SOAR/XSOAR orchestration, threat intelligence platforms, SIEM/UEBA analytics, and building cyber fusion centers. Background includes technical enablement, solution architecture for enterprise and government clients, and implementing security automation workflows across IR, TIP, and SOC use cases.
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