CVE-2025-53549 is a medium-severity SQL injection vulnerability identified in the matrix-org's matrix-rust-sdk, specifically affecting versions 0.11 and 0.12. The matrix-rust-sdk is a set of Rust libraries designed to facilitate the development of Matrix clients, which are used for decentralized communication. The vulnerability exists in the EventCache::find_event_with_relations method, which improperly neutralizes special elements used in SQL commands, leading to CWE-89: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection'). This flaw allows malicious room members to inject arbitrary SQL commands when the method is called with relation types directly provided by those members, particularly when the default SQLite-based store backend is used. Exploitation requires that the client application uses this API in a manner that directly passes untrusted relation types to the vulnerable method. Currently, no known Matrix clients use the API in this vulnerable way, reducing the likelihood of exploitation in the wild. The vulnerability has been addressed and fixed in version 0.13 of the matrix-rust-sdk. The CVSS 4.0 score is 5.2 (medium severity), reflecting network attack vector, low attack complexity, partial authentication required, no user interaction, and high impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild. This vulnerability highlights the risk posed by improper input sanitization in client-side SDKs that interact with databases, especially in decentralized communication platforms where malicious insiders may exist within chat rooms.

For European organizations using Matrix clients built on the affected versions of matrix-rust-sdk with the default SQLite backend, this vulnerability could allow malicious room members to execute arbitrary SQL commands, potentially leading to unauthorized data access, data corruption, or denial of service within the client application. Given the decentralized and federated nature of Matrix, organizations relying on such clients for internal or external communication could face confidentiality breaches or integrity violations if exploited. However, the actual impact is mitigated by the fact that no known clients currently use the vulnerable API pattern, and exploitation requires being a member of the targeted room, limiting the attack surface to insider threats or compromised accounts. Nonetheless, organizations in sectors with high regulatory requirements for data protection (e.g., finance, healthcare, government) should be cautious, as any data leakage or manipulation could have compliance and reputational consequences. The vulnerability also underscores the importance of secure coding practices in client SDKs that handle database operations, as client-side compromises can cascade into broader security issues.

1. Upgrade all matrix-rust-sdk dependencies to version 0.13 or later, where this vulnerability is fixed. 2. Audit any custom Matrix clients or applications built on matrix-rust-sdk to ensure that the EventCache::find_event_with_relations method is not called with untrusted or user-supplied relation types without proper sanitization or validation. 3. If upgrading immediately is not feasible, implement input validation and sanitization on relation types before passing them to the vulnerable method to prevent injection. 4. Consider switching from the default SQLite backend to a more robust database backend if supported, which may offer additional security controls. 5. Monitor Matrix room memberships and access controls to minimize the risk of malicious insiders exploiting this vulnerability. 6. Employ runtime application self-protection (RASP) or database activity monitoring to detect and block anomalous SQL queries originating from client applications. 7. Educate developers on secure coding practices related to database interactions, especially in decentralized communication platforms.