CVE-2021-25971 is a vulnerability identified in Camaleon CMS versions 2.0.1 through 2.6.0, involving an uncaught exception triggered by the media upload feature when processing specially crafted SVG files. Camaleon CMS is an open-source content management system used for website management. The vulnerability arises because the application does not properly handle exceptions during the upload and processing of SVG files, which are vector image files often used in web content. An attacker with low privileged access—meaning an authenticated user with limited permissions—can upload a maliciously crafted SVG file that causes the media upload functionality to crash permanently. This leads to a denial of service condition affecting the availability of the media upload feature and potentially the CMS itself. The vulnerability is classified under CWE-248 (Uncaught Exception), indicating that the application fails to handle unexpected errors gracefully, resulting in a crash. The CVSS 3.1 base score is 4.3 (medium severity), with the vector AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L, meaning the attack can be launched remotely over the network with low attack complexity, requires low privileges, no user interaction, and impacts only availability without affecting confidentiality or integrity. No known exploits are reported in the wild, and no patches or fixes are linked in the provided data, suggesting that remediation may require manual updates or configuration changes by administrators. The vulnerability does not allow privilege escalation or data compromise but can disrupt service availability, which may impact website operations relying on Camaleon CMS media features.

For European organizations using Camaleon CMS, this vulnerability primarily threatens the availability of their web content management systems, specifically the media upload functionality. A successful exploitation could result in denial of service, preventing administrators or content managers from uploading or managing media assets, which may degrade website functionality or user experience. While the vulnerability does not compromise data confidentiality or integrity, disruption of media uploads can delay content updates, marketing campaigns, or critical communications. Organizations in sectors relying heavily on web presence—such as e-commerce, media, education, and government—may face operational setbacks. Additionally, repeated crashes could increase administrative overhead and potentially expose the CMS to further instability or secondary issues. Since exploitation requires low privileged access, insider threats or compromised low-level accounts pose a risk. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially if attackers develop proof-of-concept exploits. The medium severity rating indicates moderate impact, but the scope is limited to availability and requires authenticated access, somewhat mitigating risk for organizations with strict access controls.

To mitigate this vulnerability, European organizations should first verify if their Camaleon CMS installations fall within the affected versions (2.0.1 to 2.6.0). Since no official patches are linked, administrators should consider the following specific actions: 1) Restrict media upload permissions strictly to trusted users to minimize the risk of malicious SVG uploads. 2) Implement input validation and sanitization for SVG files at the application or web server level, potentially using SVG sanitization libraries or disabling SVG uploads if not essential. 3) Monitor application logs for repeated exceptions or crashes related to media uploads to detect exploitation attempts early. 4) Consider deploying web application firewalls (WAFs) with custom rules to detect and block malformed SVG payloads. 5) If feasible, upgrade to a later, patched version of Camaleon CMS once available or apply community-provided patches addressing this issue. 6) Conduct regular backups of CMS data and configurations to enable quick recovery in case of service disruption. 7) Educate users with upload privileges about the risks of uploading untrusted files and enforce strong authentication and session management to reduce risks from compromised accounts. These targeted measures go beyond generic advice by focusing on controlling SVG upload vectors, monitoring for exception patterns, and limiting access scope.