CVE-2024-25876 is a cross-site scripting (XSS) vulnerability identified in the Header module of Enhavo CMS version 0.13.1. The vulnerability arises because the Title text field does not properly sanitize or encode user-supplied input, allowing an attacker to inject malicious scripts or HTML content. When a victim views the affected page, the injected payload executes in their browser context, potentially enabling theft of session cookies, redirection to malicious sites, or unauthorized actions performed on behalf of the user. The vulnerability requires no authentication but does require user interaction (e.g., a user visiting a crafted URL or page). The CVSS 3.1 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), scope changed (S:C), and low impact on confidentiality and integrity (C:L/I:L), with no impact on availability (A:N). This vulnerability is categorized under CWE-79, which covers improper neutralization of input during web page generation. No official patches or exploit code are currently known, but the vulnerability poses a risk to any Enhavo CMS deployment that uses the vulnerable Header module and allows user input in the Title field without proper validation or encoding.

The primary impact of this vulnerability is the potential compromise of user confidentiality and integrity through the execution of arbitrary scripts in the context of the victim's browser. This can lead to session hijacking, credential theft, phishing attacks, or unauthorized actions performed with the victim's privileges. While availability is not affected, the reputational damage and potential data breaches resulting from successful exploitation can be significant. Organizations using Enhavo CMS for public-facing websites or internal portals are at risk, especially if users with elevated privileges are targeted. The vulnerability's requirement for user interaction limits automated exploitation but does not eliminate risk, as attackers can craft phishing campaigns or malicious links to trigger the payload. The lack of an official patch increases exposure time, and the absence of known exploits suggests this is a newly disclosed issue. Overall, the impact is medium severity but could escalate if combined with other vulnerabilities or social engineering tactics.

To mitigate this vulnerability, organizations should immediately implement strict input validation and output encoding on the Title text field within the Header module of Enhavo CMS. Employ context-aware encoding (e.g., HTML entity encoding) to neutralize any injected scripts before rendering. Restrict or sanitize user input to disallow HTML or script tags in the Title field. If possible, disable or limit user ability to modify the Title field until a vendor patch is released. Employ Content Security Policy (CSP) headers to restrict script execution sources and reduce the impact of potential XSS payloads. Monitor web application logs for suspicious input patterns or repeated injection attempts. Educate users about phishing risks related to malicious links. Finally, maintain regular backups and prepare incident response plans to quickly address any exploitation attempts. Stay alert for official patches or updates from Enhavo CMS and apply them promptly once available.