CVE-2020-36423

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-07-19 · updated 2026-06-17
Weakness: CWE-319

Description

An issue was discovered in Arm Mbed TLS before 2.23.0. A remote attacker can recover plaintext because a certain Lucky 13 countermeasure doesn't properly consider the case of a hardware accelerator.

Affected products

mbedtls: before 2.16.7; from 2.17.0 before 2.23.0 — fixed in 2.16.7, 2.23.0
Debian Linux: 10.0

How to fix

Upgrade to a fixed version: mbedtls 2.16.7, 2.23.0. Check the vendor advisory for mitigations.

References

https://bugs.gentoo.org/730752
https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.7
https://github.com/ARMmbed/mbedtls/releases/tag/v2.23.0
https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html
https://bugs.gentoo.org/730752
https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.7
https://github.com/ARMmbed/mbedtls/releases/tag/v2.23.0
https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html

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