CVE-2025-6088 is a medium-severity vulnerability classified under CWE-285 (Improper Authorization) affecting the open-source project danny-avila/librechat, specifically version 0.7.8. The flaw resides in the conversation sharing feature, where the API endpoint `/api/share/conversationID` does not enforce proper authorization checks. This allows any authenticated user to access conversations of other users if they know the conversation ID. Conversation IDs are generated as UUIDv4 values server-side, which are cryptographically random and difficult to guess via brute force. However, these IDs can be leaked through less secure channels such as server logs, browser history, or screenshots, making exploitation feasible in certain scenarios. The vulnerability permits read-only access to other users' conversations, impacting confidentiality but not integrity or availability. No user interaction beyond being logged in is required, and the attack surface is limited to users who can obtain or infer valid conversation IDs. The issue has been addressed in version 0.7.9-rc1 of librechat. There are no known exploits in the wild at this time. The CVSS v3.0 score is 4.2, reflecting a network attack vector with high attack complexity, requiring low privileges and no user interaction, resulting in limited confidentiality impact and low integrity and availability impact.

For European organizations using danny-avila/librechat version 0.7.8 or earlier, this vulnerability poses a risk to the confidentiality of sensitive conversational data. Organizations relying on librechat for internal communications or customer interactions could face unauthorized disclosure of private conversations if attackers gain access to conversation IDs. This could lead to exposure of proprietary information, personal data, or strategic communications, potentially violating GDPR requirements and damaging trust. The read-only nature limits the risk of data tampering or service disruption, but confidentiality breaches alone can have significant compliance and reputational consequences. Since exploitation requires authenticated access and knowledge of conversation IDs, the threat is more pronounced in environments where user credentials or session tokens are compromised or where conversation IDs are inadvertently exposed through logs or client-side artifacts. European entities with strict data privacy regulations must prioritize remediation to avoid regulatory penalties and maintain data protection standards.

1. Upgrade to librechat version 0.7.9-rc1 or later where the authorization checks on the `/api/share/conversationID` endpoint are properly enforced. 2. Implement strict access control validation on all API endpoints handling sensitive data, ensuring users can only access resources they are authorized for. 3. Audit and sanitize server-side logs and client-side storage to prevent leakage of conversation IDs or other sensitive identifiers. 4. Educate users and administrators about the risks of sharing screenshots or browser histories that may contain sensitive UUIDs. 5. Employ monitoring and anomaly detection to identify unusual access patterns to conversation data, which may indicate exploitation attempts. 6. Consider additional encryption or tokenization of conversation IDs to reduce the risk of ID enumeration or leakage. 7. Enforce strong authentication and session management controls to reduce the risk of unauthorized authenticated access.