CVE-2024-23508 is a high-severity reflected Cross-Site Scripting (XSS) vulnerability identified in the bPlugins PDF Poster – PDF Embedder Plugin for WordPress, affecting versions up to and including 2.1.17. This vulnerability arises due to improper neutralization of user-supplied input during web page generation, classified under CWE-79. Specifically, the plugin fails to adequately sanitize or encode input parameters that are reflected back in the HTTP response, allowing an attacker to inject malicious scripts. When a victim visits a crafted URL containing malicious payloads, these scripts execute in the context of the victim’s browser, potentially leading to session hijacking, credential theft, defacement, or redirection to malicious sites. The CVSS v3.1 base score of 7.1 reflects the vulnerability's characteristics: it is remotely exploitable over the network (AV:N), requires no privileges (PR:N), but does require user interaction (UI:R), and impacts confidentiality, integrity, and availability to a limited extent (C:L/I:L/A:L). The scope is changed (S:C), indicating that exploitation could affect resources beyond the vulnerable component. No public exploits are currently known in the wild, but the vulnerability’s presence in a widely used WordPress plugin makes it a significant risk, especially given WordPress’s popularity and the common use of PDF embedding plugins for content delivery.

For European organizations, this vulnerability poses a considerable risk, especially for entities relying on WordPress websites that embed PDFs using the affected plugin. Exploitation could lead to unauthorized access to user sessions, theft of sensitive information, or distribution of malware via compromised websites. This is particularly critical for sectors handling sensitive data such as finance, healthcare, education, and government services. The reflected XSS can be leveraged in targeted phishing campaigns against employees or customers, undermining trust and potentially leading to regulatory non-compliance under GDPR due to data breaches. Additionally, website defacement or redirection could damage brand reputation and cause operational disruptions. Given the widespread adoption of WordPress across Europe, the vulnerability could affect a broad range of organizations, from small businesses to large enterprises.

Organizations should immediately verify if their WordPress installations use the PDF Poster – PDF Embedder Plugin and identify the version in use. Since no patch links are currently available, administrators should consider temporarily disabling or removing the plugin until a secure update is released. Web application firewalls (WAFs) can be configured to detect and block typical XSS payloads targeting this plugin’s parameters. Additionally, implementing Content Security Policy (CSP) headers can help mitigate the impact of XSS by restricting script execution sources. Regular security audits and monitoring of web server logs for suspicious requests can aid in early detection of exploitation attempts. Organizations should also educate users about the risks of clicking on suspicious links and ensure that all WordPress components are kept up to date once patches become available. Finally, deploying security plugins that sanitize inputs and outputs can provide an additional layer of defense.