CVE-2025-53534 is a high-severity vulnerability affecting the RatPanel server operation and maintenance management panel developed by tnb-labs, specifically versions from 2.3.19 up to but not including 2.5.6. The vulnerability stems from an authentication bypass caused by a primary weakness (CWE-305) in the panel's handling of backend login paths. An attacker who discovers the backend login URL—through weak default paths, brute-force attacks, or other reconnaissance methods—can exploit this flaw to execute arbitrary system commands or fully compromise hosts managed by the panel without needing to authenticate. The root cause lies in the misuse of the CleanPath middleware from the github.com/go-chi/chi package, which is intended to sanitize URL paths but fails to process the r.URL.Path correctly. This leads to misinterpretation of request paths, allowing unauthorized access and remote code execution (RCE). The vulnerability does not require user interaction and can be exploited remotely over the network with low attack complexity. The flaw has been addressed in RatPanel version 2.5.6, which corrects the URL path processing logic. Although no known exploits are currently reported in the wild, the potential for severe impact is significant given the ability to execute system commands and take over managed hosts without authentication.

For European organizations using RatPanel versions between 2.3.19 and 2.5.5, this vulnerability poses a critical risk to operational security and infrastructure integrity. Successful exploitation can lead to full system compromise, including unauthorized command execution and control over multiple managed hosts. This can result in data breaches, service disruptions, lateral movement within networks, and potential deployment of ransomware or other malware. Given that RatPanel is used for server operation and maintenance, attackers could manipulate critical infrastructure components, causing widespread outages or data loss. The high confidentiality, integrity, and availability impacts make this vulnerability particularly dangerous. European entities in sectors such as finance, healthcare, manufacturing, and government—where server management panels are integral—could face severe operational and reputational damage. Additionally, the lack of required user interaction and the remote network exploitability increase the likelihood of automated or targeted attacks.

European organizations should immediately audit their infrastructure to identify any deployments of RatPanel within the affected version range (>=2.3.19 and <2.5.6). The primary mitigation is to upgrade all instances of RatPanel to version 2.5.6 or later, where the URL path processing flaw is fixed. Until upgrades can be completed, organizations should restrict access to the RatPanel backend login paths using network-level controls such as IP whitelisting, VPN-only access, or firewall rules to limit exposure to trusted administrators. Implementing strong monitoring and alerting on unusual access patterns or command execution attempts on servers managed by RatPanel is critical. Additionally, organizations should review and harden default paths and credentials to prevent brute-force discovery of backend URLs. Employing web application firewalls (WAFs) with custom rules to detect and block suspicious requests targeting RatPanel login endpoints can provide an additional layer of defense. Finally, conducting penetration testing focused on authentication bypass and URL path manipulation can help validate the effectiveness of mitigations.