CVE-2024-27558 identifies a Cross Site Scripting (XSS) vulnerability in Stupid Simple CMS version 1.2.4, specifically within the blog title field of the settings. XSS vulnerabilities occur when an application includes untrusted user input in web pages without proper validation or escaping, allowing attackers to inject malicious scripts. In this case, the blog title input is not properly sanitized, enabling an attacker to craft a payload that executes arbitrary JavaScript in the context of users viewing the affected CMS interface or blog pages. The vulnerability is classified under CWE-79, which covers improper neutralization of input during web page generation. The CVSS 3.1 base score is 6.1 (medium severity), with the vector indicating that the attack can be performed remotely over the network (AV:N), requires low attack complexity (AC:L), no privileges (PR:N), but does require user interaction (UI:R). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact affects confidentiality and integrity at a low level (C:L/I:L), but does not affect availability (A:N). No known exploits are currently reported in the wild, and no official patches or vendor information are available. Given the lack of vendor/project details, this CMS appears to be a niche or less widely known product. The vulnerability allows attackers to potentially steal session cookies, perform actions on behalf of authenticated users, or deface content, depending on the victim's privileges and the CMS deployment context.

For European organizations using Stupid Simple CMS 1.2.4, this XSS vulnerability poses a moderate risk primarily to confidentiality and integrity of user sessions and data. Attackers could exploit this flaw to hijack authenticated sessions, leading to unauthorized access or data manipulation. This is particularly concerning for organizations hosting public-facing blogs or internal portals where sensitive information or user credentials might be exposed. The requirement for user interaction means phishing or social engineering could be used to lure victims into triggering the malicious script. While availability is not directly impacted, the reputational damage and potential data breaches could have regulatory consequences under GDPR, especially if personal data is compromised. Since the CMS is not widely recognized, the impact is likely limited to organizations that have adopted this specific product, which may include small to medium enterprises or niche sectors. However, any exploitation could undermine trust and compliance efforts.

Given the absence of official patches, European organizations should implement the following specific mitigations: 1) Immediately audit all instances of Stupid Simple CMS 1.2.4 to identify affected deployments. 2) Apply manual input validation and output encoding on the blog title field within the CMS source code, ensuring all user-supplied input is properly sanitized against script injection. 3) Employ Content Security Policy (CSP) headers to restrict the execution of inline scripts and reduce the impact of XSS payloads. 4) Educate users and administrators about the risk of phishing or social engineering attacks that could trigger this vulnerability. 5) Monitor web logs and user activity for suspicious behavior indicative of exploitation attempts. 6) Consider isolating or replacing the CMS with a more secure and actively maintained platform if remediation is not feasible. 7) Use web application firewalls (WAFs) configured to detect and block common XSS attack patterns targeting the blog title parameter. These steps go beyond generic advice by focusing on source code remediation, user awareness, and layered defenses tailored to this specific vulnerability.