CVE-2025-11769 is a stored Cross-Site Scripting (XSS) vulnerability identified in the WordPress Content Flipper plugin developed by aumsrini. The flaw exists in all versions up to and including 0.1 due to improper neutralization of input during web page generation, specifically in the handling of the 'bgcolor' attribute within the 'flipper_front' shortcode. The vulnerability stems from insufficient input sanitization and lack of proper output escaping, allowing an attacker with authenticated contributor-level access or higher to inject arbitrary JavaScript code into pages. When other users visit these pages, the injected scripts execute in their browsers, potentially compromising their session cookies, credentials, or enabling actions on their behalf. The vulnerability is network exploitable (AV:N), requires low attack complexity (AC:L), but does require privileges (PR:L) and does not need user interaction (UI:N). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact affects confidentiality and integrity but not availability, with a CVSS v3.1 base score of 6.4 (medium severity). No patches or public exploits are currently available. This vulnerability highlights the risks of insufficient input validation in WordPress plugins, especially those that allow shortcode attributes to influence page content dynamically. Attackers leveraging this flaw could compromise site visitors or administrators, leading to data theft or site defacement.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on WordPress sites with the Content Flipper plugin installed. Exploitation could lead to theft of sensitive user data such as authentication cookies, enabling session hijacking and unauthorized access to user accounts. This can result in data breaches, reputational damage, and potential regulatory penalties under GDPR if personal data is compromised. The integrity of website content can be undermined by injecting malicious scripts, possibly leading to phishing attacks targeting site visitors or administrators. While availability is not directly impacted, the indirect effects of compromised user trust and potential blacklisting by search engines or security services can affect business operations. Since exploitation requires contributor-level access, insider threats or compromised accounts pose a particular risk. Organizations with public-facing WordPress sites that allow multiple contributors should be especially vigilant. The lack of known exploits in the wild provides a window for proactive mitigation before widespread attacks occur.

European organizations should immediately audit their WordPress installations to identify if the Content Flipper plugin (version 0.1 or earlier) is in use. If found, disable or remove the plugin until a patched version is released. In the absence of an official patch, implement strict input validation and output escaping for the 'bgcolor' shortcode attribute by customizing the plugin code or using security plugins that enforce content sanitization. Limit contributor-level access strictly to trusted users and review user permissions regularly to reduce the risk of malicious insiders or compromised accounts. Employ Web Application Firewalls (WAFs) with rules to detect and block XSS payloads targeting shortcode parameters. Monitor website logs for unusual activity or injection attempts. Educate content contributors about the risks of injecting untrusted content. Additionally, implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts. Regularly update WordPress core and all plugins to their latest versions to benefit from security fixes. Finally, prepare incident response plans to quickly address any detected exploitation attempts.