matrix-rust-sdk is an implementation of a Matrix client-server library in Rust, and matrix-sdk-crypto is the Matrix encryption library. Prior to version 0.6, when a user requests a room key from their devices, the software correctly remembers the request. When the user receives a forwarded room key, the software accepts it without checking who the room key came from. This allows homeservers to try to insert room keys of questionable validity, potentially mounting an impersonation attack. Version 0.6 fixes this issue.
Use CWE-287, Matrix vendor hub and Matrix-Rust-Sdk product page to widen CVE-2022-39252 into its surrounding weakness, vendor, and product context.
Compare it with CVE-2025-66622 for nearby disclosures in the same product family.