What’s Vulnerable › Vulnerabilities

CVE-2020-16150

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-09-02 · updated 2026-06-17
• Weakness: CWE-203

Description

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

• mbedtls: before 2.7.17; from 2.8.0 before 2.16.8; from 2.17.0 before 2.24.0 — fixed in 2.16.8, 2.24.0, 2.7.17
• Debian Linux: 10.0
• Fedoraproject Fedora: 31, 32, 33

How to fix

Upgrade to a fixed version: mbedtls 2.16.8, 2.24.0, 2.7.17. Check the vendor advisory for mitigations.

References

• https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5OSOFUD6UTGTDDSQRS62BPXDU52I6PUA/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IRPBHCQKZXHVKOP5O5EWE7P76AWGUXQJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OD3NM6GD73CTFFRBKG5G2ACXGG7QQHCC/
• https://tls.mbed.org/tech-updates/security-advisories
• https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-09-1
• https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5OSOFUD6UTGTDDSQRS62BPXDU52I6PUA/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IRPBHCQKZXHVKOP5O5EWE7P76AWGUXQJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OD3NM6GD73CTFFRBKG5G2ACXGG7QQHCC/
• https://tls.mbed.org/tech-updates/security-advisories
• https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-09-1

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