CVE-2026-17528 in nice-select2
Summary
by MITRE • 07/28/2026
Versions of the package nice-select2 before 2.4.1 are vulnerable to Cross-site Scripting (XSS) via the <select> element. An attacker can supply a malicious payload that is rendered directly into the DOM without proper sanitization, causing arbitrary script execution in a victim’s browser when they view or interact with the affected page.
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Analysis
by VulDB Data Team • 07/28/2026
The vulnerability described affects the nice-select2 javascript library, which is commonly used to enhance html select elements with custom styling and functionality. This particular flaw exists in versions prior to 241 and represents a classic cross-site scripting vulnerability that can have serious implications for web application security. The issue manifests when the library processes user-supplied input through the <select> element without adequate sanitization or encoding mechanisms, creating an attack vector that allows malicious actors to inject arbitrary javascript code into the page.
The technical nature of this vulnerability stems from improper handling of user input within the DOM manipulation process. When a developer incorporates nice-select2 into their web application and fails to properly validate or sanitize data passed to the select element, an attacker can craft malicious payloads that get executed in the context of the victim's browser. This occurs because the library directly injects user-provided content into html elements without appropriate output encoding or sanitization measures. The vulnerability specifically affects the rendering process where the library transforms standard html select elements into enhanced custom dropdown interfaces, making it particularly dangerous as it operates within the normal user interaction flow.
The operational impact of this vulnerability extends beyond simple script execution, potentially allowing attackers to perform session hijacking, data theft, or further exploitation through techniques such as credential harvesting or redirection attacks. Users who interact with affected pages may unknowingly execute malicious code that can persistently compromise their browser environment and access sensitive information. The vulnerability is particularly concerning in environments where users may have elevated privileges or access to sensitive data, as it could enable privilege escalation or lateral movement within the application. According to CWE classification, this represents a CWE-79: Cross-site Scripting vulnerability, which falls under the broader category of injection flaws that affect web applications.
The exploitation of this vulnerability typically requires an attacker to convince a victim to interact with a maliciously crafted page or form element that contains the XSS payload within the select options. This can occur through various attack vectors including phishing campaigns, compromised web pages, or social engineering tactics that lead users to submit malicious data into forms using the vulnerable library. Security practitioners should consider this vulnerability in relation to ATT&CK framework technique T1566.001 which covers spearphishing with a link and T1203 which involves exploitation for persistence through browser-based attacks.
Mitigation strategies for this vulnerability include immediate upgrading to version 241 or later of the nice-select2 library, where the XSS sanitization issues have been addressed. Additionally, developers should implement comprehensive input validation and output encoding practices within their applications, ensuring that any user-supplied data passed to select elements is properly sanitized before processing. Organizations should also consider implementing Content Security Policy headers as an additional defense layer to prevent execution of unauthorized scripts even if a vulnerability is exploited. Regular security audits of third-party libraries and dependencies remain critical for maintaining application security posture and preventing similar vulnerabilities from being introduced into web applications.