CVE-2025-61594 in URI Gem
Summary
by MITRE • 12/30/2025
URI is a module providing classes to handle Uniform Resource Identifiers. In versions prior to 0.12.5, 0.13.3, and 1.0.4, a bypass exists for the fix to CVE-2025-27221 that can expose user credentials. When using the `+` operator to combine URIs, sensitive information like passwords from the original URI can be leaked, violating RFC3986 and making applications vulnerable to credential exposure. Versions 0.12.5, 0.13.3, and 1.0.4 fix the issue.
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Analysis
by VulDB Data Team • 02/26/2026
The vulnerability described in CVE-2025-61594 represents a significant security flaw in URI handling modules that affects multiple versions of a popular library. This issue specifically targets the process of URI concatenation using the '+' operator, which was previously thought to be adequately protected against credential leakage. The vulnerability arises from an insufficient implementation of the fix for CVE-2025-27221, creating a bypass that allows sensitive information to be inadvertently exposed during URI manipulation operations. This flaw directly violates the principles outlined in RFC3986, which governs the proper handling and composition of uniform resource identifiers, making it a critical concern for applications that process user credentials through URI structures.
The technical implementation of this vulnerability occurs when developers utilize the '+' operator to combine URI objects, which should normally sanitize and remove sensitive components such as passwords, usernames, and authentication tokens. However, the bypass allows these credentials to persist in the resulting URI structure, creating a scenario where authentication information can be exposed through URI concatenation operations. The flaw specifically impacts applications that dynamically construct URIs by combining base URIs with additional components, where the original URI contains sensitive authentication data that should be stripped during the concatenation process. This represents a direct violation of security principles that mandate credential sanitization during URI operations, as outlined in the CWE-546 security weakness classification.
The operational impact of this vulnerability extends beyond simple credential exposure to potentially enable broader attack vectors including credential theft, session hijacking, and unauthorized access to protected resources. Applications that rely on URI concatenation for API calls, service discovery, or resource access may inadvertently leak user credentials to logs, network traffic, or intermediate systems that process these URIs. The vulnerability is particularly concerning because it operates silently, with no explicit error messages or warnings, making it difficult to detect during normal application operation. Attackers could exploit this flaw by constructing malicious URI combinations that preserve sensitive information, potentially gaining access to systems or resources that should remain protected. The exposure of credentials through URI manipulation also violates fundamental security practices that require sensitive information to be properly handled and sanitized during all processing operations, as referenced in the ATT&CK framework's credential access tactics.
Organizations should immediately upgrade to the patched versions 0.12.5, 0.13.3, and 1.0.4 to address this vulnerability, as these releases contain the necessary fixes to prevent credential leakage during URI concatenation operations. Security teams should conduct comprehensive audits of their applications to identify all instances where URI concatenation occurs, particularly focusing on operations that combine URIs containing authentication information. Additional mitigations include implementing URI sanitization checks, logging URI operations for security monitoring, and establishing automated testing procedures to verify proper credential handling during URI manipulation. The fix addresses the core issue by ensuring that sensitive components are properly stripped during concatenation operations, aligning with RFC3986 requirements for secure URI handling and preventing the exposure of user credentials that could compromise system security.