CVE-2025-6040 is a Cross-Site Request Forgery (CSRF) vulnerability affecting all versions of the Easy Flashcards WordPress plugin developed by sagesony. The vulnerability arises from missing or incorrect nonce validation on the 'ef_settings_submenu' administrative page. Nonces in WordPress are security tokens used to verify that requests to perform sensitive actions originate from legitimate users and not from forged requests. Due to the absence of proper nonce checks, an unauthenticated attacker can craft malicious requests that, if an authenticated site administrator is tricked into clicking a specially crafted link or visiting a malicious webpage, will be executed with the administrator's privileges. This allows the attacker to update plugin settings and inject malicious scripts into the site, leading to Cross-Site Scripting (CWE-79) attacks. The vulnerability has a CVSS 3.1 base score of 6.1, indicating a medium severity level. The attack vector is network-based with low attack complexity, no privileges required, but user interaction (administrator clicking a link) is necessary. The scope is changed, meaning the vulnerability affects resources beyond the initially vulnerable component. While no known exploits are currently reported in the wild, the vulnerability poses a significant risk due to the potential for persistent script injection and subsequent compromise of site visitors or administrative accounts. The lack of available patches at the time of reporting increases the urgency for mitigation through other means.

For European organizations using WordPress sites with the Easy Flashcards plugin, this vulnerability can lead to unauthorized modification of plugin settings and injection of malicious scripts. This compromises the integrity of the website and can lead to theft of sensitive data from site visitors, including login credentials or personal information, via XSS attacks. The availability of the site is not directly impacted, but reputational damage and loss of user trust can be significant. Organizations in sectors such as education, e-commerce, and government that rely on WordPress for public-facing or internal portals are particularly at risk. The vulnerability could also be leveraged as a foothold for further attacks within the network if administrative credentials or session tokens are stolen. Given the widespread use of WordPress in Europe and the potential for targeted phishing campaigns to trick administrators, the threat could have a broad impact, especially on small and medium enterprises (SMEs) that may lack dedicated security teams.

1. Immediate mitigation should include disabling or uninstalling the Easy Flashcards plugin until a security patch is released. 2. If the plugin is essential, restrict administrative access to trusted IP addresses and enforce multi-factor authentication (MFA) for all WordPress administrators to reduce the risk of compromised credentials. 3. Implement Content Security Policy (CSP) headers to limit the impact of injected scripts. 4. Educate administrators about phishing and social engineering risks to prevent them from clicking on malicious links. 5. Monitor web server and WordPress logs for unusual POST requests to the 'ef_settings_submenu' page and any unexpected changes in plugin settings. 6. Regularly update WordPress core and all plugins to the latest versions once the vendor releases a patch addressing this vulnerability. 7. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious requests targeting the vulnerable endpoint. 8. Conduct periodic security audits and vulnerability scans focusing on plugin security and nonce validation mechanisms.