Logging of Private Backup Key in Matrix Rust SDK Version 0.7.0

CVE-2024-34353

What is CVE-2024-34353?

The matrix-sdk-crypto crate, part of the Matrix Rust SDK project, is an implementation of a Matrix end-to-end encryption state machine in Rust. In Matrix, the server-side key backup stores encrypted copies of Matrix message keys. This facilitates key sharing between a user's devices and provides a redundant copy in case all devices are lost. The key backup uses asymmetric cryptography, with each server-side key backup assigned a unique public-private key pair. Due to a logic bug introduced in commit 71136e44c03c79f80d6d1a2446673bc4d53a2067, matrix-sdk-crypto version 0.7.0 will sometimes log the private part of the backup key pair to Rust debug logs (using the tracing crate). This issue has been resolved in matrix-sdk-crypto version 0.7.1. No known workarounds are available.

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