What’s Vulnerable › Vulnerabilities

CVE-2021-24119

• Severity: medium (CVSS 4.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-07-14 · updated 2026-06-17
• Weakness: CWE-203

Description

In Trusted Firmware Mbed TLS 2.24.0, a side-channel vulnerability in base64 PEM file decoding allows system-level (administrator) attackers to obtain information about secret RSA keys via a controlled-channel and side-channel attack on software running in isolated environments that can be single stepped, especially Intel SGX.

Affected products

• mbedtls: before 2.26.0 — fixed in 2.26.0
• Debian Linux: 9.0, 10.0
• Fedoraproject Fedora: 33, 34

How to fix

Upgrade to a fixed version: mbedtls 2.26.0. Check the vendor advisory for mitigations.

References

• https://github.com/ARMmbed/mbedtls/releases
• https://github.com/UzL-ITS/util-lookup/blob/main/cve-vulnerability-publication.md
• https://lists.debian.org/debian-lts-announce/2021/11/msg00021.html
• https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DRRVY7DMTX3ECFNZKDYTSFEG5AI2HBC6/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EYJW7HAW3TDV2YMDFYXP3HD6WRQRTLJW/
• https://github.com/ARMmbed/mbedtls/releases
• https://github.com/UzL-ITS/util-lookup/blob/main/cve-vulnerability-publication.md
• https://lists.debian.org/debian-lts-announce/2021/11/msg00021.html
• https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html
• https://lists.debian.org/debian-lts-announce/2025/06/msg00034.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DRRVY7DMTX3ECFNZKDYTSFEG5AI2HBC6/

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