CVE-2025-1087 is a critical security vulnerability identified in the Kong Inc. Insomnia desktop application versions prior to 11.0.2. The vulnerability is classified as CWE-20 (Improper Input Validation) and CWE-94 (Improper Control of Generation of Code), indicating that the root cause lies in insufficient validation of user-supplied input when processing template strings within the application. This flaw enables attackers to perform template injection attacks, which can lead to arbitrary JavaScript code execution in the context of the Insomnia application. Since Insomnia is a desktop client used primarily for API testing and development, the execution of arbitrary code could allow an attacker to manipulate the application’s behavior, access sensitive data such as API keys or tokens stored within the app, or potentially pivot to further compromise the host system. The vulnerability is remotely exploitable without requiring authentication (AV:N/AC:L/PR:N), but does require user interaction (UI:A), such as opening a maliciously crafted template or project file. The CVSS 4.0 base score of 9.3 reflects the critical nature of this vulnerability, with high impact on confidentiality, integrity, and availability, and a wide scope affecting the application and potentially the underlying system. No known exploits are currently reported in the wild, and no official patches or updates are linked yet, though the fixed version is 11.0.2 or later. The vulnerability was publicly disclosed on May 9, 2025, with the initial reservation of the CVE in February 2025.

For European organizations, this vulnerability poses a significant risk especially to software developers, DevOps teams, and security professionals who rely on Insomnia for API development and testing. Exploitation could lead to unauthorized code execution, resulting in theft of sensitive credentials, manipulation of API requests and responses, and potential lateral movement within corporate networks. This could compromise the confidentiality of proprietary data and intellectual property, disrupt development workflows, and degrade trust in software supply chains. Given that Insomnia is often used in environments that interact with critical infrastructure APIs or cloud services, successful exploitation could have cascading effects on operational integrity. Furthermore, the requirement for user interaction means phishing or social engineering campaigns could be leveraged to trick users into opening malicious templates, increasing the attack surface. The absence of known exploits currently provides a window for proactive mitigation, but the critical severity demands immediate attention to prevent potential targeted attacks against European enterprises.

European organizations should immediately verify the version of Insomnia in use and upgrade to version 11.0.2 or later once available. Until patches are applied, organizations should implement strict controls on the import and opening of template files or projects from untrusted sources. Security awareness training should emphasize the risks of opening files from unknown origins to mitigate social engineering vectors. Network segmentation and endpoint protection solutions should be configured to monitor and block suspicious JavaScript execution within the Insomnia application context. Additionally, organizations can consider restricting the use of Insomnia to trusted users and environments, and enforce application whitelisting to prevent unauthorized code execution. Regular audits of API keys and tokens stored in Insomnia should be conducted to detect potential compromise. Finally, monitoring for unusual application behavior or unexpected network communications from Insomnia clients can provide early detection of exploitation attempts.