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Ubuntu 20.04: Linux Kernel Critical Issue VMSCAPE CVE-2025

Linuxsecurity •LinuxSecurity Advisories • November 19, 2025

A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.04 LTS Summary: Several security issues were fixed in the Linux kernel. Software Description: - linux-aws-fips: Linux kernel for Amazon Web Services (AWS) systems with FIPS - linux-fips: Linux kernel with FIPS - linux-gcp-fips: Linux kernel for Google Cloud Platform (GCP) systems with FIPS Details: Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi discovered that the Linux kernel contained insufficient branch predictor isolation between a guest and a userspace hypervisor for certain processors. This flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this to expose sensitive information from the host OS. (CVE-2025-40300) Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - HSI subsystem;

The problem can be corrected by updating your system to the following package versions: Ubuntu 20.04 LTS linux-image-5.4.0-1126-fips 5.4.0-1126.136 Available with Ubuntu Pro linux-image-5.4.0-1152-aws-fips 5.4.0-1152.162+fips1 Available with Ubuntu Pro linux-image-5.4.0-1155-gcp-fips 5.4.0-1155.164+fips1 Available with Ubuntu Pro linux-image-aws-fips 5.4.0.1152.99 Available with Ubuntu Pro linux-image-aws-fips-5.4 5.4.0.1152.99 Available with Ubuntu Pro linux-image-fips 5.4.0.1126.123 Available with Ubuntu Pro linux-image-fips-5.4 5.4.0.1126.123 Available with Ubuntu Pro linux-image-gcp-fips 5.4.0.1155.97 Available with Ubuntu Pro linux-image-gcp-fips-5.4 5.4.0.1155.97 Available with Ubuntu Pro After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.

CVE-2023-52854, CVE-2024-35867, CVE-2024-50061, CVE-2024-56664, CVE-2025-21727, CVE-2025-37838, CVE-2025-38352, CVE-2025-40300

CVE-2023-52854, CVE-2024-35867, CVE-2024-50061, CVE-2024-56664,

CVE-2025-21727, CVE-2025-37838, CVE-2025-38352, CVE-2025-40300

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.

Linux Kernel Vulnerabilities Expose Sensitive Information via VMSCAPE A series of vulnerabilities in the Linux kernel, identified by researchers Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi, allow attackers in guest virtual machines to potentially expose sensitive information from the host operating system. This flaw, known as VMSCAPE, affects various Linux kernel versions and has been linked to insufficient branch predictor isolation. Multiple updates have been issued to address these vulnerabilities. 90 sources 16

Extracted Entities

Ubuntu 20.04: Linux Kernel Critical Issue VMSCAPE CVE-2025

The full story

Extracted Entities

Attack Types (1)

Companies (3)

CVEs (8)

Platforms (3)

Vulnerabilities (1)