CVE-2025-61594 is a vulnerability classified under CWE-212 (Improper Removal of Sensitive Information Before Storage or Transfer) affecting the Ruby 'uri' module, which provides classes for handling Uniform Resource Identifiers (URIs). The issue arises in versions prior to 0.12.5, 0.13.3, and 1.0.4, where a bypass exists for the fix implemented in CVE-2025-27221. Specifically, when developers use the '+' operator to concatenate or combine URI objects, sensitive information such as user credentials (e.g., passwords embedded in the URI) can be inadvertently retained and exposed. This behavior violates RFC3986, which governs URI syntax and security considerations. The vulnerability stems from improper sanitization or removal of sensitive data during URI manipulation, leading to potential leakage of credentials in logs, error messages, or transmitted data. The flaw does not require privileges, authentication, or user interaction to be exploited, and the attack vector is network-based. Despite the low CVSS score of 2.7, the vulnerability poses a confidentiality risk by exposing sensitive authentication data. The issue is resolved in versions 0.12.5, 0.13.3, and 1.0.4 of the Ruby 'uri' module, which properly sanitize sensitive information when combining URIs. No known exploits have been reported in the wild, but the vulnerability should be addressed proactively.

For European organizations, the primary impact of CVE-2025-61594 is the potential exposure of sensitive user credentials embedded within URIs. This can lead to unauthorized access if credentials are leaked through logs, error reports, or network transmissions. Organizations that develop or maintain web applications, APIs, or services using Ruby and the affected 'uri' module versions are at risk. Credential exposure can result in compromised user accounts, unauthorized data access, and potential lateral movement within networks. Although the vulnerability does not directly affect system availability or integrity, the confidentiality breach can have cascading effects, including regulatory non-compliance under GDPR due to inadequate protection of sensitive information. The low CVSS score reflects the limited scope and ease of exploitation, but the risk is amplified in environments where credentials are embedded in URIs and handled insecurely. European sectors with high reliance on Ruby-based web services, such as fintech, e-commerce, and public services, may face increased risk if patches are not applied.

1. Upgrade the Ruby 'uri' module to versions 0.12.5, 0.13.3, or 1.0.4 or later, which contain the fix for this vulnerability. 2. Audit application code to identify any usage of the '+' operator for combining URIs and refactor to avoid concatenation methods that retain sensitive information. 3. Avoid embedding sensitive credentials directly in URIs; use secure authentication mechanisms such as OAuth tokens or session-based authentication instead. 4. Implement strict logging policies to sanitize or exclude sensitive data from logs and error messages. 5. Conduct code reviews and static analysis focusing on URI handling to detect potential leaks of sensitive information. 6. Educate developers on secure URI handling practices and the risks of embedding credentials in URIs. 7. Monitor network traffic and application logs for unexpected exposure of credentials. 8. If immediate upgrade is not feasible, implement application-layer filters or proxies to sanitize URIs before processing or logging.