CVE-2023-24609: Matrixssl

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

Matrix SSL 4.x through 4.6.0 and Rambus TLS Toolkit have a length-subtraction integer overflow for Client Hello Pre-Shared Key extension parsing in the TLS 1.3 server. An attacked device calculates an SHA-2 hash over at least 65 KB (in RAM). With a large number of crafted TLS messages, the CPU becomes heavily loaded. This occurs in tls13VerifyBinder and tls13TranscriptHashUpdate.

Affected products

• Matrixssl Matrixssl: from 4.0.0, up to and including 4.6.0
• Rambus TLS Toolkit: affected versions not specified

Published 2023-12-22. Last modified 2026-06-17.