Summary
Introduction
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.
Workarounds
None.
References
For more information
If you have any questions or comments about this advisory, please email us at security at matrix.org.
Impact
Due to a logic bug introduced in https://github.com/matrix-org/matrix-rust-sdk/pull/2961/commits/71136e44c03c79f80d6d1a2446673bc4d53a2067, the matrix-sdk-crypto crate version 0.7.0 will sometimes log the private part of the backup key pair to Rust debug logs (using the tracing crate).
CVE-2024-34353 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.7.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
This issue has been resolved in matrix-sdk-crypto version 0.7.1.
Frequently Asked Questions
- What is CVE-2024-34353? CVE-2024-34353 is a medium-severity security vulnerability in matrix-sdk-crypto (rust), affecting versions = 0.7.0. It is fixed in 0.7.1.
- How severe is CVE-2024-34353? CVE-2024-34353 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of matrix-sdk-crypto are affected by CVE-2024-34353? matrix-sdk-crypto (rust) versions = 0.7.0 is affected.
- Is there a fix for CVE-2024-34353? Yes. CVE-2024-34353 is fixed in 0.7.1. Upgrade to this version or later.
- Is CVE-2024-34353 exploitable, and should I be worried? Whether CVE-2024-34353 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-34353 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-34353? Upgrade
matrix-sdk-cryptoto 0.7.1 or later.