CVE-2025-26545 identifies a Cross-Site Request Forgery (CSRF) vulnerability in the WordPress plugin 'Related Posts Line-up-Exactly by Milliard' developed by shisuh. This plugin, which facilitates related post displays on WordPress sites, contains a flaw that allows attackers to trick authenticated users into submitting unauthorized requests. The CSRF vulnerability enables attackers to perform actions without the user's consent, such as injecting malicious scripts that result in Stored Cross-Site Scripting (XSS). Stored XSS can lead to persistent script execution in the context of the victim's browser, enabling session hijacking, defacement, or malware distribution. The affected versions are all versions up to 0.0.22. The vulnerability was published on February 13, 2025, with no CVSS score assigned and no known exploits in the wild at the time of reporting. The absence of a patch link suggests that a fix may not yet be available, increasing the urgency for mitigation. The attack requires the victim to be authenticated on the vulnerable site and to visit a malicious webpage controlled by the attacker, which then triggers the CSRF attack. This vulnerability impacts the confidentiality, integrity, and availability of affected WordPress sites by enabling unauthorized actions and persistent malicious code injection.

The impact of CVE-2025-26545 is significant for organizations using the vulnerable plugin. Successful exploitation can lead to persistent Stored XSS, allowing attackers to steal user credentials, hijack sessions, deface websites, or distribute malware to site visitors. This compromises the confidentiality and integrity of user data and the website content. The availability of the site could also be affected if attackers inject disruptive scripts or cause site malfunction. Since WordPress powers a large portion of the web, and plugins are widely used to extend functionality, this vulnerability can affect a broad range of organizations, from small businesses to large enterprises relying on WordPress for their online presence. The lack of an available patch increases the window of exposure. Attackers could leverage this vulnerability to target high-profile websites or those with privileged user roles, amplifying the potential damage. Additionally, the stored nature of the XSS means that every visitor to the compromised site could be exposed to malicious payloads, increasing the scope of impact.

Organizations should immediately assess whether they use the 'Related Posts Line-up-Exactly by Milliard' plugin and identify the version in use. Until an official patch is released, administrators should consider disabling or uninstalling the plugin to eliminate the attack surface. Implementing Web Application Firewall (WAF) rules that detect and block CSRF attempts and suspicious POST requests targeting the plugin's endpoints can provide temporary protection. Enforcing strict Content Security Policy (CSP) headers can help mitigate the impact of stored XSS by restricting script execution sources. Site administrators should also ensure that users have minimal necessary privileges to reduce potential damage from compromised accounts. Monitoring web server and application logs for unusual activity related to the plugin can help detect exploitation attempts. Once a patch is available, prompt application of updates is critical. Additionally, educating users about the risks of visiting untrusted websites while authenticated on sensitive sites can reduce the likelihood of CSRF exploitation.