CVE-2020-16150: Arm Mbed TLS

Medium severity, CVSS 5.5. EPSS: 0.4% chance of exploitation in the next 30 days.

A Lucky 13 timing side channel in mbedtls_ssl_decrypt_buf in library/ssl_msg.c in Trusted Firmware Mbed TLS through 2.23.0 allows an attacker to recover secret key information. This affects CBC mode because of a computed time difference based on a padding length.

Affected products

• Arm Mbed TLS: before 2.7.17 (fixed in 2.7.17); from 2.8.0, before 2.16.8 (fixed in 2.16.8); from 2.17.0, before 2.24.0 (fixed in 2.24.0)
• Debian Debian Linux: version 10.0 only
• Fedoraproject Fedora: version 31 only; version 32 only; version 33 only

Published 2020-09-02. Last modified 2026-06-17.