CVE-2025-58921 is a reflected Cross-site Scripting (XSS) vulnerability identified in the Arevico WP Tactical Popup WordPress plugin, specifically affecting versions up to and including 1.1. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows attackers to inject malicious JavaScript code that is reflected back to users without adequate sanitization. When a victim clicks on a crafted URL or interacts with a maliciously crafted popup, the injected script executes in their browser context. This can lead to theft of session cookies, credentials, or other sensitive information accessible via the browser, thereby compromising confidentiality. The CVSS v3.1 base score is 7.1, indicating a high severity level, with an attack vector of network (remote), low attack complexity, no privileges required, but requiring user interaction. The scope is unchanged, meaning the vulnerability affects only the vulnerable component. The integrity impact is low since the attacker cannot modify server-side data directly, and availability impact is none. Currently, there are no known exploits in the wild, but the vulnerability is publicly disclosed and published as of October 22, 2025. The plugin is commonly used to create tactical popups on WordPress sites, which are prevalent in marketing, e-commerce, and media sectors. The lack of a patch link suggests that a fix may not yet be available, emphasizing the need for interim mitigations.

For European organizations, this vulnerability poses a significant risk to websites using the WP Tactical Popup plugin, particularly those handling sensitive user data or providing critical services. Successful exploitation can lead to session hijacking, credential theft, or unauthorized actions performed in the context of the victim user, potentially resulting in data breaches or reputational damage. Since WordPress powers a substantial portion of European websites, including SMEs and large enterprises, the attack surface is considerable. Industries such as e-commerce, finance, healthcare, and media are especially vulnerable due to their reliance on interactive web components and the value of their data. The reflected XSS nature means phishing or social engineering campaigns could be used to lure users into clicking malicious links, increasing the risk to end users and employees. While availability is not directly impacted, the confidentiality breach can have regulatory consequences under GDPR, including fines and mandatory breach notifications. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as attackers often develop exploits rapidly after disclosure.

Organizations should prioritize monitoring for updates from Arevico and apply patches immediately once available. Until a patch is released, implement strict input validation and output encoding on all user-supplied data related to the popup functionality, either by customizing the plugin code or using web application firewalls (WAFs) with rules targeting reflected XSS patterns. Deploy Content Security Policy (CSP) headers to restrict script execution sources, mitigating the impact of injected scripts. Educate users and staff about the risks of clicking unsolicited links, especially those leading to popup interactions. Conduct regular security assessments and penetration tests focusing on web application vulnerabilities, including XSS. Consider temporarily disabling or replacing the WP Tactical Popup plugin with a more secure alternative if patching is delayed. Maintain comprehensive logging and monitoring to detect suspicious activities indicative of exploitation attempts. Finally, ensure compliance with GDPR by preparing incident response plans for potential data breaches stemming from this vulnerability.