CVE-1999-0604 is a medium-severity vulnerability affecting version 1.0 of the Selena Sol WebStore shopping cart CGI program, specifically the "web_store.cgi" script. The vulnerability arises from an incorrect configuration of this CGI program, which can lead to the unintended disclosure of private information. As a CGI-based web application component, "web_store.cgi" handles user interactions and data related to e-commerce transactions. The misconfiguration likely allows unauthorized remote attackers to access sensitive data without authentication, as indicated by the CVSS vector (AV:N/AC:L/Au:N/C:P/I:N/A:N), meaning the attack can be performed over the network with low attack complexity and no authentication required. The vulnerability impacts confidentiality but does not affect integrity or availability. Given the age of the vulnerability (published in 1999) and the lack of available patches or known exploits in the wild, it is probable that this software is either obsolete or replaced in most environments. However, legacy systems still running Selena Sol WebStore 1.0 could be at risk of information leakage, potentially exposing customer data or internal business information through improper access controls or directory traversal issues inherent in the CGI script's configuration.

For European organizations, the impact of this vulnerability primarily concerns the confidentiality of sensitive customer and business data handled by the WebStore application. Disclosure of private information could lead to privacy violations, regulatory non-compliance (notably with GDPR), reputational damage, and potential financial losses due to loss of customer trust. Although the vulnerability does not allow modification or denial of service, the exposure of private data in e-commerce platforms can facilitate further attacks such as identity theft, fraud, or targeted phishing campaigns. Organizations still operating legacy e-commerce systems with this software are at risk, especially small to medium enterprises that may not have migrated to modern platforms. The medium severity rating reflects that while the vulnerability is not critical, the ease of exploitation and lack of authentication requirements make it a tangible risk if the affected software is in use.

Given that no official patches are available for this vulnerability, European organizations should prioritize the following mitigation steps: 1) Immediate assessment and inventory of web applications to identify any instances of Selena Sol WebStore 1.0 in use. 2) If found, isolate or decommission the affected system to prevent exposure. 3) If decommissioning is not immediately feasible, implement strict network-level access controls such as IP whitelisting or VPN-only access to limit exposure of the CGI script to trusted users. 4) Employ web application firewalls (WAFs) with custom rules to detect and block suspicious requests targeting "web_store.cgi". 5) Conduct thorough configuration reviews to ensure that directory listings, debug modes, or verbose error messages are disabled. 6) Plan and execute migration to modern, supported e-commerce platforms with active security maintenance. 7) Regularly monitor logs for unusual access patterns to the CGI script. These steps go beyond generic advice by focusing on compensating controls and legacy system management, critical in the absence of patches.