What’s Vulnerable › Vulnerabilities

CVE-2021-44732

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-12-20 · updated 2026-06-17
• Weakness: CWE-415

Description

Mbed TLS before 3.0.1 has a double free in certain out-of-memory conditions, as demonstrated by an mbedtls_ssl_set_session() failure.

Affected products

• mbedtls: before 2.16.12; from 2.17.0 before 2.28.0 — fixed in 2.16.12, 2.28.0
• Debian Linux: 10.0
• TrustedFirmware Mbed TLS: 3.0.0, 3.0.0-preview1

How to fix

Upgrade to a fixed version: mbedtls 2.16.12, 2.28.0. Check the vendor advisory for mitigations.

References

• https://bugs.gentoo.org/829660
• https://github.com/ARMmbed/mbedtls/releases
• https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.12
• https://github.com/ARMmbed/mbedtls/releases/tag/v2.28.0
• https://github.com/ARMmbed/mbedtls/releases/tag/v3.1.0
• https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html
• https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-12
• https://bugs.gentoo.org/829660
• https://github.com/ARMmbed/mbedtls/releases
• https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.12
• https://github.com/ARMmbed/mbedtls/releases/tag/v2.28.0
• https://github.com/ARMmbed/mbedtls/releases/tag/v3.1.0

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