CVE-2026-1776 is a path traversal vulnerability classified under CWE-22 affecting Camaleon CMS versions 2.4.5.0 through 2.9.0 prior to commit f54a77e. The vulnerability exists in the AWS S3 uploader backend's download_private_file functionality, which fails to validate file paths properly. Unlike the local uploader implementation that uses a valid_folder_path? check to restrict file access, the AWS uploader backend omits this validation, allowing directory traversal sequences (e.g., ../) to be injected via the file parameter. This flaw enables any authenticated user, including those with low privileges, to read arbitrary files from the web server's filesystem. Critical system files such as /etc/passwd can be accessed, potentially exposing sensitive system and user information. This vulnerability represents a bypass of an earlier partial fix (CVE-2024-46987), indicating that the root cause was not fully addressed. The vulnerability requires authentication but no user interaction beyond sending crafted requests. The CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N) indicates network attack vector, low attack complexity, partial authentication, no user interaction, and high confidentiality impact with no integrity or availability impact. No public exploits have been reported yet, but the vulnerability poses a significant risk to deployments using the AWS S3 storage backend in Camaleon CMS. Remediation involves updating to a fixed version or applying patches that enforce proper path validation in the AWS uploader backend.

The primary impact of CVE-2026-1776 is unauthorized disclosure of sensitive files on the web server hosting Camaleon CMS. Attackers with low-level authenticated access can exploit this vulnerability to read arbitrary files, potentially exposing system configuration, credentials, private keys, or other sensitive data. This can lead to further compromise, including privilege escalation, lateral movement, or data leakage. Organizations relying on Camaleon CMS with AWS S3 backend for content management may face confidentiality breaches, regulatory compliance violations, and reputational damage. Since the vulnerability does not affect integrity or availability directly, the immediate risk is data exposure. However, the disclosed information could facilitate more severe attacks. The ease of exploitation (low complexity, network accessible) and the fact that low-privileged users can exploit it increase the threat level. Enterprises with sensitive data or critical infrastructure managed via Camaleon CMS are particularly at risk. The lack of known exploits in the wild currently reduces immediate threat but does not eliminate the urgency for mitigation.

To mitigate CVE-2026-1776, organizations should: 1) Upgrade Camaleon CMS to a version that includes the fix for this vulnerability (post commit f54a77e) as soon as it becomes available. 2) If immediate upgrade is not possible, implement strict input validation on the file parameter in the download_private_file function to reject directory traversal sequences and enforce path restrictions equivalent to the local uploader's valid_folder_path? check. 3) Restrict access to the AWS S3 uploader backend functionality to only trusted users or roles with a demonstrated need, minimizing the attack surface. 4) Monitor web server logs for suspicious file access patterns indicative of directory traversal attempts. 5) Employ web application firewalls (WAFs) with rules to detect and block path traversal payloads targeting the vulnerable endpoint. 6) Review and limit permissions of authenticated users to reduce the impact of potential exploitation. 7) Conduct thorough security assessments and penetration testing focusing on file upload and download functionalities. 8) Maintain up-to-date backups and incident response plans in case of data exposure. These targeted measures go beyond generic advice by focusing on the specific vulnerable component and attack vector.