CVE-2025-8350 is a critical security vulnerability identified in the BiEticaret CMS developed by Inrove Software and Internet Services, affecting versions from 2.1.13 through 19022026. The vulnerability is characterized by Execution After Redirect (EAR) and missing authentication for critical functions (CWE-698 and CWE-306). EAR occurs when an application continues to execute code after issuing an HTTP redirect, which can lead to unintended actions being performed. In this case, the missing authentication allows attackers to bypass login mechanisms and access protected functions without credentials. Additionally, the vulnerability enables HTTP response splitting attacks, which can be exploited to manipulate web responses, conduct cache poisoning, cross-site scripting (XSS), and other malicious activities. The CVSS v3.1 base score of 9.8 reflects the high severity, with network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The scope is unchanged (S:U), but the impact on confidentiality (C:H), integrity (I:H), and availability (A:H) is high. The vendor was contacted early but did not respond or provide patches, leaving systems exposed. No known exploits are currently reported in the wild, but the nature of the vulnerability makes it highly exploitable. This vulnerability threatens the core security properties of affected CMS installations, potentially allowing attackers to fully compromise websites, steal sensitive data, manipulate content, or disrupt services.

For European organizations, especially those operating e-commerce platforms or websites using BiEticaret CMS, this vulnerability poses a critical risk. Exploitation can lead to unauthorized access to administrative functions, data breaches involving customer information, financial data theft, and website defacement or downtime. The HTTP response splitting aspect can facilitate further attacks such as session hijacking, phishing, or malware distribution targeting European users. Given the high CVSS score and lack of vendor response, organizations face a heightened risk of targeted attacks or opportunistic exploitation. The impact extends to regulatory compliance issues under GDPR due to potential data exposure. Disruption of e-commerce services can also result in significant financial losses and reputational damage. The vulnerability's ease of exploitation without authentication or user interaction increases the likelihood of rapid compromise once discovered by attackers.

Since no official patches are available, European organizations should implement immediate compensating controls. These include restricting access to the BiEticaret CMS administrative interfaces via IP whitelisting or VPNs, deploying web application firewalls (WAFs) with custom rules to detect and block suspicious redirect patterns and HTTP response splitting attempts, and conducting thorough logging and monitoring for anomalous activities related to redirects and authentication bypass attempts. Organizations should also isolate affected CMS instances from critical internal networks to limit lateral movement. Regular backups and incident response plans should be updated to prepare for potential exploitation. Additionally, organizations should consider migrating to alternative CMS platforms with active security support if feasible. Close monitoring of threat intelligence feeds for emerging exploits targeting this vulnerability is essential. Finally, organizations should engage with the vendor or community to encourage patch development and share mitigation strategies.