CVE-2025-54542 is a medium-severity vulnerability identified in OpenSolution's QuickCMS version 6.8. The core issue stems from the application transmitting sensitive authentication credentials—specifically, usernames and passwords—via HTTP GET requests. This practice exposes credentials in the URL query string, which is inherently insecure because URLs are commonly logged in browser history, server logs, proxy logs, and potentially third-party analytics tools. An attacker with local access to the victim's browser history can extract these credentials and subsequently impersonate the user by logging into the CMS. The vulnerability is classified under CWE-598, which highlights the improper use of GET requests for sensitive data transmission. Notably, the vendor has not provided detailed information about the vulnerable version range beyond confirming version 6.8 as affected, leaving uncertainty about other versions. The CVSS 4.0 base score is 6.9, reflecting a medium severity level, with the attack vector being local (AV:L), low attack complexity (AC:L), and no privileges or user interaction required (PR:N, UI:N). The vulnerability impacts confidentiality significantly (VC:H) but does not affect integrity or availability. No known exploits are currently in the wild, and no patches have been published yet. This vulnerability primarily affects environments where QuickCMS 6.8 is deployed and where local attackers can access browser histories, such as shared workstations or compromised endpoints.

For European organizations using QuickCMS 6.8, this vulnerability poses a tangible risk to the confidentiality of user credentials. If an attacker gains local access to a user's machine—through physical access, malware, or insider threats—they can retrieve stored URLs containing plaintext credentials. This can lead to unauthorized access to the CMS, enabling attackers to modify website content, inject malicious code, or exfiltrate sensitive data managed by the CMS. Given that CMS platforms often serve as the backbone for corporate websites, intrusions could damage brand reputation, lead to data breaches, or facilitate further lateral movement within the network. The impact is particularly concerning for organizations handling sensitive or regulated data, such as financial institutions, healthcare providers, or government agencies within Europe. Additionally, the lack of vendor response and absence of patches increase the window of exposure. The vulnerability's reliance on local access limits remote exploitation but does not eliminate risk in environments with shared devices or insufficient endpoint security controls.

To mitigate this vulnerability, European organizations should immediately audit their QuickCMS deployments to identify version 6.8 installations. Until a vendor patch is available, organizations should consider the following specific actions: 1) Restrict physical and logical access to workstations where QuickCMS is accessed, ensuring only authorized personnel can use these systems. 2) Implement endpoint security solutions that prevent unauthorized access to browser histories or employ browser privacy modes that do not retain URL histories. 3) Encourage or enforce the use of secure authentication mechanisms, such as POST requests for login forms, by customizing or patching the CMS code if feasible. 4) Monitor CMS access logs for suspicious login patterns that may indicate credential compromise. 5) Educate users about the risks of shared devices and the importance of logging out and clearing browser histories after CMS use. 6) Consider deploying web application firewalls (WAFs) to detect anomalous requests and potentially block attempts to exploit this vulnerability. 7) Plan for an upgrade or migration to a newer, secure CMS version once available. These targeted mitigations go beyond generic advice by focusing on local access controls, browser history management, and CMS-specific configuration adjustments.