CVE-2026-2145 identifies a cross-site scripting (XSS) vulnerability in the cym1102 nginxWebUI product, specifically affecting versions 4.3.0 through 4.3.7. The flaw exists in the web management interface component, within an unspecified function located at /adminPage/conf/check. The vulnerability is triggered by manipulating the nginxDir argument, which is not properly sanitized before being reflected in the web interface. This improper input validation allows an attacker to inject malicious JavaScript code that executes in the context of an authenticated user's browser session. The attack vector is remote and does not require prior authentication, though it does require user interaction (e.g., clicking a crafted link). The CVSS 4.0 score of 5.1 reflects a medium severity, considering the ease of exploitation (low complexity), no privileges required, but user interaction is necessary. The vulnerability does not impact confidentiality or availability directly but can compromise integrity by enabling script injection, potentially leading to session hijacking, credential theft, or further attacks on the internal network. The vendor cym1102 has been notified but has not yet released a patch or mitigation guidance, and while a public exploit exists, no active exploitation has been observed in the wild. Organizations relying on this web management interface should be aware of the risk and take immediate steps to mitigate exposure.

For European organizations, this vulnerability poses a moderate risk primarily to the confidentiality and integrity of web management sessions. Successful exploitation could allow attackers to execute arbitrary scripts, steal session cookies, or perform unauthorized actions within the management interface. This could lead to unauthorized configuration changes, exposure of sensitive operational data, or pivoting to other internal systems. Organizations in sectors such as telecommunications, critical infrastructure, and managed service providers using cym1102 nginxWebUI are particularly at risk. The remote exploitability without authentication increases the attack surface, especially if the management interface is exposed to the internet or accessible from less secure internal networks. The lack of a vendor patch increases the urgency for interim mitigations. While no active exploitation is currently known, the availability of a public exploit increases the likelihood of future attacks, making proactive defense essential.

1. Immediately restrict access to the nginxWebUI management interface by implementing network-level controls such as VPNs, IP whitelisting, or firewall rules to limit exposure to trusted administrators only. 2. Employ web application firewalls (WAF) with custom rules to detect and block suspicious input patterns targeting the nginxDir parameter. 3. Educate administrators to avoid clicking on untrusted links or opening suspicious emails that could trigger the XSS attack. 4. Monitor logs for unusual requests to /adminPage/conf/check and anomalous user activity within the management interface. 5. If feasible, temporarily disable or isolate the vulnerable web management interface until a vendor patch is released. 6. Regularly check for vendor updates or community patches and apply them promptly once available. 7. Consider deploying Content Security Policy (CSP) headers to reduce the impact of potential XSS attacks by restricting script execution sources. 8. Conduct internal penetration testing to verify the effectiveness of mitigations and identify any additional attack vectors.