CVE-2025-24764 is a medium-severity vulnerability classified under CWE-79, which pertains to improper neutralization of input during web page generation, commonly known as Cross-site Scripting (XSS). Specifically, this vulnerability affects the product '(Simply) Guest Author Name' developed by A. Jones, up to version 4.36. The vulnerability is DOM-based XSS, meaning that malicious scripts are injected and executed in the Document Object Model (DOM) environment of the user's browser without proper sanitization or validation of user-supplied input. This flaw allows an attacker with low privileges (PR:L) to execute a reflected or stored script that can manipulate the client-side environment. The CVSS 3.1 vector indicates that the attack can be launched remotely over the network (AV:N) with low attack complexity (AC:L), requires some user interaction (UI:R), and results in a scope change (S:C), affecting confidentiality, integrity, and availability to a limited extent (C:L/I:L/A:L). Although no known exploits are currently in the wild and no patches have been linked, the vulnerability's presence in a web-facing component that handles guest author inputs makes it a significant risk for web applications relying on this product. The DOM-based nature means that the malicious payload is executed in the victim's browser context, potentially leading to session hijacking, defacement, or redirection to malicious sites.

For European organizations using '(Simply) Guest Author Name'—likely in content management or guest authoring roles—this vulnerability could lead to unauthorized script execution in users' browsers. This can compromise user credentials, enable session hijacking, or facilitate phishing attacks by injecting malicious content. The impact extends to data confidentiality breaches, integrity violations through unauthorized content manipulation, and availability issues if the injected scripts disrupt normal application behavior. Given the scope change in the CVSS vector, the vulnerability could affect multiple users or systems if exploited in a multi-tenant environment. European organizations handling sensitive user data or operating in regulated sectors (e.g., finance, healthcare, government) could face compliance risks under GDPR if personal data is exposed or manipulated. The requirement for user interaction reduces the immediacy of the threat but does not eliminate it, especially if attackers can craft convincing social engineering campaigns. The absence of known exploits suggests a window for proactive mitigation before widespread exploitation occurs.

1. Immediate review and update of input validation and output encoding mechanisms within '(Simply) Guest Author Name' to ensure all user-supplied data is properly sanitized before being reflected in the DOM. 2. Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS payloads. 3. Employ security-focused code reviews and automated scanning tools specifically targeting DOM-based XSS patterns in the application codebase. 4. Educate users and administrators about the risks of clicking on untrusted links or interacting with suspicious content that could trigger XSS attacks. 5. Monitor web application logs and user reports for unusual behavior indicative of XSS exploitation attempts. 6. If possible, isolate guest authoring functionalities behind additional authentication or privilege layers to limit exposure. 7. Engage with the vendor or community maintaining '(Simply) Guest Author Name' to obtain patches or updates addressing this vulnerability as they become available. 8. Consider deploying web application firewalls (WAFs) with custom rules to detect and block typical XSS attack vectors targeting this product.