Back Linuxsecurity

Ubuntu 24.04 LTS mbedtls Critical Denial of Service USN-8123

Linuxsecurity •LinuxSecurity Advisories • March 25, 2026

A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS Summary: Several security issues were fixed in mbedtls. Software Description: - mbedtls: Lightweight crypto and SSL/TLS library Details: It was discovered that Mbed TLS incorrectly handled memory allocation failures. A remote attacker could possibly use this issue to crash the program. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2021-44732) Jonathan Winzig discovered that Mbed TLS incorrectly handled crafted inputs. A remote attacker could possibly use this issue to crash the program, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS. (CVE-2024-23775) It was discovered that Mbed TLS incorrectly handled the TLS handshake. A remote attacker could possibly use this issue to break the security guarantees of the TLS handshake. (CVE-2025-27810)

The problem can be corrected by updating your system to the following package versions: Ubuntu 24.04 LTS libmbedcrypto7t64 2.28.8-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedtls-dev 2.28.8-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedtls14t64 2.28.8-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedx509-1t64 2.28.8-1ubuntu0.1~esm1 Available with Ubuntu Pro Ubuntu 22.04 LTS libmbedcrypto7 2.28.0-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedtls-dev 2.28.0-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedtls14 2.28.0-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedx509-1 2.28.0-1ubuntu0.1~esm1 Available with Ubuntu Pro Ubuntu 20.04 LTS libmbedcrypto3 2.16.4-1ubuntu2+esm1 Available with Ubuntu Pro libmbedtls-dev 2.16.4-1ubuntu2+esm1 Available with Ubuntu Pro libmbedtls12 2.16.4-1ubuntu2+esm1 Available with Ubuntu Pro libmbedx509-0 2.16.4-1ubuntu2+esm1 Available with Ubuntu Pro Ubuntu 18.04 LTS libmbedcrypto1 2.8.0-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedtls-dev 2.8.0-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedtls10 2.8.0-1ubuntu0.1~esm1 Available with Ubuntu Pro libmbedx509-0 2.8.0-1ubuntu0.1~esm1 Available with Ubuntu Pro In general, a standard system update will make all the necessary changes.

CVE-2021-44732, CVE-2024-23775, CVE-2025-27810, CVE-2025-47917, CVE-2025-48965, CVE-2025-52496, CVE-2025-52497

CVE-2021-44732, CVE-2024-23775, CVE-2025-27810, CVE-2025-47917,

CVE-2025-48965, CVE-2025-52496, CVE-2025-52497

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Critical Mbed TLS Vulnerabilities Affect Multiple Ubuntu Releases Multiple vulnerabilities have been identified in Mbed TLS, impacting Ubuntu 18.04 LTS, 20.04 LTS, 22.04 LTS, and 24.04 LTS. The vulnerabilities include improper handling of memory allocation failures (CVE-2021-44732), crafted inputs leading to denial of service (CVE-2024-23775), and issues with the TLS handshake (CVE-2025-27810). These flaws could allow remote attackers to crash applications or compromise TLS security guarantees. The vulnerabilities were disclosed on March 25, 2026, and patches are available for affected systems. Users are advised to update their systems to mitigate risks associated with these vulnerabilities. The issues were discovered by researchers including Jonathan Winzig, Linh Le, and Ngan Nguyen. The vulnerabilities are critical due to their potential impact on security and service availability. 2 sources 72

Extracted Entities

Ubuntu 24.04 LTS mbedtls Critical Denial of Service USN-8123

The full story

Extracted Entities

Attack Types (1)

Companies (1)

CVEs (7)