CVE-2020-36421: Arm Mbed TLS

Medium severity, CVSS 5.3. EPSS: 1.5% chance of exploitation in the next 30 days.

An issue was discovered in Arm Mbed TLS before 2.23.0. Because of a side channel in modular exponentiation, an RSA private key used in a secure enclave could be disclosed.

Affected products

• Arm Mbed TLS: before 2.16.7 (fixed in 2.16.7); from 2.17.0, before 2.23.0 (fixed in 2.23.0)
• Debian Debian Linux: version 10.0 only

Published 2021-07-19. Last modified 2026-06-17.