CVE-2026-49367: IntelliJ IDEA Guest Account Command Execution Vulnerability

Technical summary

CVE-2026-49367 is an authorization bypass vulnerability in IntelliJ IDEA that allows command execution through the guest user account. The flaw stems from improper access controls (CWE-862: Missing Authorization) that fail to restrict command execution capabilities to appropriately privileged accounts. An authenticated user with guest-level permissions can trigger command execution with the privileges of the IntelliJ IDEA process. The vulnerability requires network access and user interaction but does not require administrative privileges to trigger, making it accessible to any user with login credentials.

Business impact

For development teams, this vulnerability poses a risk to code integrity and intellectual property. An attacker with guest credentials could execute arbitrary commands within the IDE, potentially exfiltrating source code, injecting malicious code into projects, or deploying backdoors. In shared development environments or corporate settings where multiple developers use IntelliJ IDEA instances, a compromised guest account could serve as a foothold for lateral movement. Build pipelines and CI/CD systems that rely on IntelliJ IDEA plugins or integrations may also be at risk if automated processes use guest-level accounts.

Affected systems

JetBrains IntelliJ IDEA versions prior to 2026.1.1 are affected. Organizations running IntelliJ IDEA 2026.1 or earlier should prioritize verification and patching. Both community and commercial editions are likely affected, though the exact product variant coverage should be confirmed against JetBrains' official advisory. Other JetBrains IDEs built on the IntelliJ platform should be monitored for similar issues.

Exploitability

Exploitability is moderate to high in practical environments. An attacker requires valid credentials (even guest-level access), which may be obtained through credential theft, social engineering, or account reuse. Once authenticated, the attacker needs to interact with the IDE to trigger command execution—this is not a wormable, unauthenticated remote code execution flaw. However, in organizations with permissive guest account policies or shared development machines, the barrier to exploitation is low. The network-accessible nature (AV:N in the CVSS vector) means remote exploitation is possible without physical access.

Remediation

Upgrade IntelliJ IDEA to version 2026.1.1 or later. Organizations unable to patch immediately should enforce strict access controls on guest accounts, disable guest access where feasible, and monitor IDE activity for suspicious command execution. Network segmentation can reduce the attack surface by limiting remote access to development machines. Review IDE plugin permissions and disable unnecessary plugins that might be abused for code execution.

Patch guidance

Download and install IntelliJ IDEA version 2026.1.1 or the latest available version from JetBrains' official download portal. For enterprise deployments using JetBrains' toolbox or centralized license management, coordinate patching with your internal deployment process. Test the patched version in a non-production environment first to ensure compatibility with existing projects and plugins. Verify patch application by checking the version number in Help > About or your IDE settings.

Detection guidance

Monitor IDE logs and system audit trails for unexpected command execution originating from IntelliJ IDEA processes, particularly when triggered by guest-level user accounts. Use endpoint detection and response (EDR) tools to flag command execution events from the IDE executable path. Network monitoring can identify unusual outbound connections from development machines. Review IDE activity logs if available and correlate them with system-level command execution logs. Guest account authentication and subsequent command execution patterns should trigger alerting in mature SOCs.

Why prioritize this

This vulnerability scores 8.0 (HIGH) on CVSS 3.1 and warrants priority patching because it combines authenticated access with high-impact consequences (confidentiality, integrity, and availability all affected). While it does not currently appear on CISA's KEV catalog, the combination of network accessibility, low attack complexity, and the critical nature of development environments makes this a strong candidate for rapid exploitation in targeted campaigns. Development teams are often attractive targets for supply chain attacks, and a compromised IDE could affect downstream software security.

Risk score, explained

The CVSS 3.1 score of 8.0 reflects a HIGH-severity vulnerability due to the following factors: Network accessibility (AV:N) allows remote exploitation; low attack complexity (AC:L) means no special conditions are required beyond user interaction; low privilege requirements (PR:L) enable any authenticated user to exploit; required user interaction (UI:R) is a limiting factor but typical for IDE workflows. The impact metrics—high confidentiality (C:H), integrity (I:H), and availability (A:H)—indicate that a successful exploitation affects all three security pillars. The combination of these factors places this in the upper-high severity range, justifying immediate attention.

Frequently asked questions