CVE-2026-2506 is a stored cross-site scripting (XSS) vulnerability identified in the EM Cost Calculator plugin for WordPress, maintained by motahar1. The vulnerability affects all versions up to and including 2.3.1. It stems from improper neutralization of input (CWE-79) during web page generation, specifically the failure to escape the 'customer_name' field before rendering it in the administrative interface. An unauthenticated attacker can submit malicious JavaScript payloads via the 'customer_name' input, which the plugin stores without sanitization. When an administrator accesses the EMCC Customers page, the malicious script executes in their browser context. This can lead to session hijacking, privilege escalation, or other attacks leveraging the administrator's elevated permissions. The vulnerability has a CVSS v3.1 base score of 6.1, reflecting its medium severity, with an attack vector of network (remote), low attack complexity, no privileges required, but requiring user interaction (admin viewing the page). The scope is changed as the vulnerability affects the confidentiality and integrity of the system. No patches or official fixes are currently linked, and no known exploits have been reported in the wild. The vulnerability highlights the importance of proper output encoding and input validation in WordPress plugins, especially those handling administrative data.

The impact of CVE-2026-2506 is significant for organizations using the EM Cost Calculator plugin on WordPress sites, particularly those with multiple administrators. Successful exploitation allows unauthenticated attackers to inject persistent malicious scripts that execute in the context of an administrator's browser. This can lead to theft of admin session cookies, enabling account takeover, unauthorized changes to plugin or site settings, and potential pivoting to further compromise the WordPress installation or underlying infrastructure. The confidentiality of administrative credentials and sensitive customer data may be compromised, and the integrity of the site content or configuration could be undermined. Although availability is not directly impacted, the resulting compromise could lead to site defacement or downtime. The vulnerability's requirement for user interaction (admin viewing the infected page) limits automated exploitation but does not eliminate risk, especially in environments with frequent admin access. Organizations with high-value WordPress deployments or those in regulated industries face increased risk from this vulnerability.

To mitigate CVE-2026-2506, organizations should first check for and apply any available updates or patches from the plugin vendor once released. In the absence of an official patch, immediate mitigations include disabling or uninstalling the EM Cost Calculator plugin to eliminate the attack surface. Administrators should be trained to avoid viewing untrusted or suspicious customer entries until the vulnerability is resolved. Implementing a Web Application Firewall (WAF) with rules to detect and block malicious script payloads targeting the 'customer_name' parameter can reduce exploitation risk. Additionally, hardening WordPress admin access by enforcing multi-factor authentication (MFA) and restricting admin page access by IP or VPN can limit exposure. Regularly auditing plugin inputs and outputs for proper sanitization and escaping is recommended. Monitoring logs for unusual admin page access or suspicious input submissions can help detect exploitation attempts. Finally, consider isolating administrative interfaces from public internet access where feasible.