CVE-2026-64815: 
JetBrains IntelliJ IDEA vulnerability analysis and mitigation

CVE-2026-64815 is an arbitrary code injection vulnerability (CWE-94) in JetBrains IntelliJ IDEA that allows attackers to inject and execute arbitrary code via maliciously crafted UI Designer form files (.form). It affects all versions of IntelliJ IDEA before 2026.2 and was disclosed on July 23, 2026. The NVD assigns a CVSS v3.1 base score of 9.8 (Critical), while JetBrains (as CNA) rates it 8.1 (High) due to a higher attack complexity assessment (GitHub Advisory, JetBrains Advisory).

The vulnerability is classified as CWE-94 (Improper Control of Generation of Code / Code Injection) and resides in IntelliJ IDEA's UI Designer component, which processes .form XML-based files used to define GUI layouts. When a developer opens a maliciously crafted .form file, the IDE fails to properly neutralize or validate embedded code constructs, allowing arbitrary code to be injected and executed within the IDE's runtime context. The attack vector is network-based (e.g., a developer cloning a malicious repository or receiving a crafted project), and no authentication or user interaction beyond opening the file is required according to NVD's assessment, though JetBrains rates attack complexity as High (GitHub Advisory, JetBrains Advisory).

Successful exploitation results in full compromise of confidentiality, integrity, and availability on the affected developer workstation, as the injected code executes with the privileges of the IntelliJ IDEA process. An attacker could exfiltrate source code, credentials, SSH keys, and other sensitive developer assets, or use the compromised machine as a pivot point for lateral movement into internal networks or CI/CD pipelines. The total technical impact makes this particularly dangerous in software supply chain attack scenarios where developers routinely open third-party or community-contributed project files (GitHub Advisory).

As of the time of disclosure, there is no public proof-of-concept exploit and no evidence of in-the-wild exploitation. CISA's SSVC assessment classifies exploitation as "none" and the vulnerability as not automatable, reflecting the requirement for a developer to open a malicious .form file. The EPSS score is approximately 0.31–0.33%, placing it in the 26th percentile for exploitation likelihood within 30 days. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog (GitHub Advisory, JetBrains Advisory).

1. Craft malicious .form file: Create a UI Designer form file containing embedded code injection payloads that exploit IntelliJ IDEA's form file parsing logic to execute arbitrary code when processed by the IDE.
2. Deliver the payload: Host the malicious project (containing the crafted .form file) on a public or private code repository (e.g., GitHub, GitLab), or distribute it via email, file sharing, or a dependency.
3. Social engineering: Lure a developer using a vulnerable version of IntelliJ IDEA (before 2026.2) into cloning or opening the malicious project — for example, by posing as a legitimate open-source contribution or sample project.
4. Trigger code execution: When the developer opens the project in IntelliJ IDEA, the IDE processes the .form file and the injected code executes automatically within the IDE's runtime context, without requiring further interaction.
5. Achieve objective: The attacker's payload runs with the developer's privileges, enabling data exfiltration (source code, credentials, API keys), persistence, or lateral movement into connected systems (GitHub Advisory, JetBrains Advisory).

• File System: Unexpected .form files in project directories with unusual or obfuscated XML content; new or modified files in user home directories (e.g., .ssh/, credential stores) shortly after opening a project.
• Process: Unusual child processes spawned by the IntelliJ IDEA JVM process (e.g., cmd.exe, powershell.exe, bash, curl, wget, python) that are not typical IDE operations.
• Network: Unexpected outbound network connections from the IntelliJ IDEA process to unknown external IP addresses or domains, particularly shortly after opening a project containing .form files.
• Logs: IDE log files (idea.log) showing unexpected class loading, reflection calls, or errors related to UI Designer form parsing; OS-level audit logs recording process creation by the IDE process.

JetBrains has released a fix in IntelliJ IDEA version 2026.2; all users should upgrade immediately (JetBrains Advisory). As a temporary workaround until patching is possible, avoid opening UI Designer .form files from untrusted or unverified sources, including cloned repositories from unknown contributors. Organizations should enforce code review policies that inspect .form files before they are opened in the IDE, and consider restricting IDE access to vetted project sources.

Coverage of CVE-2026-64815 has been limited to automated vulnerability tracking platforms and security news aggregators such as CyberPress and VulDB, with no notable independent researcher commentary or significant social media discussion identified at this time (JetBrains Advisory, GitHub Advisory).