CVE-2024-40640

Technical Description

vodozemac is an open source implementation of Olm and Megolm in pure Rust. Versions before 0.7.0 of vodozemac use a non-constant time base64 implementation for importing key material for Megolm group sessions and `PkDecryption` Ed25519 secret keys. This flaw might allow an attacker to infer some information about the secret key material through a side-channel attack. The use of a non-constant time base64 implementation might allow an attacker to observe timing variations in the encoding and decoding operations of the secret key material. This could potentially provide insights into the underlying secret key material. The impact of this vulnerability is considered low because exploiting the attacker is required to have access to high precision timing measurements, as well as repeated access to the base64 encoding or decoding processes. Additionally, the estimated leakage amount is bounded and low according to the referenced paper. This has been patched in commit 734b6c6948d4b2bdee3dd8

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References