USN-7863-1: Linux kernel vulnerabilities

Q: Which systems are exposed to the VMSCAPE issue?

The issue is relevant to systems running a userspace hypervisor on certain processors where untrusted guest VMs are present. A guest attacker could potentially expose sensitive information from the host operating system.

Q: What access would an attacker need to exploit VMSCAPE?

The attacker would need to operate from within a guest virtual machine. The described impact is disclosure of sensitive information from the host OS.

Q: What other kernel areas are covered by this update?

The update also corrects issues in the DMA engine, GPU drivers, HSI, Ethernet team driver, TTY drivers, Ext4, timers, DCCP, IPv6, NET/ROM, SCTP, and USB sound devices. The advisory states these issues could possibly be used to compromise the system.

Published Nov 6, 2025

Updated

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: - DMA engine subsystem; - GPU drivers; - HSI subsystem; - Ethernet team driver; - TTY drivers; - Ext4 file system; - Timer subsystem; - DCCP (Datagram Congestion Control Protocol); - IPv6 networking; - NET/ROM layer; - SCTP protocol; - USB sound devices; (CVE-2021-47294, CVE-2021-47330, CVE-2023-52574, CVE-2023-52650, CVE-2024-50006, CVE-2024-50299, CVE-2024-53124, CVE-2024-53150, CVE-2024-56767, CVE-2025-37838, CVE-2025-38352)

Affected Software

43 affected componentsFixes available

All of the following

ubuntu/linux-image-4.4.0-1150-kvm<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-4.4.0-1187-aws<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-4.4.0-274-generic<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-4.4.0-274-lowlatency<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-aws<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-generic<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-generic-lts-xenial<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-kvm<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-lowlatency<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-lowlatency-lts-xenial<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-virtual<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-virtual-lts-xenial<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=16.04

All of the following

ubuntu/linux-image-4.4.0-1149-aws<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=14.04

All of the following

ubuntu/linux-image-4.4.0-274-generic<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=14.04

All of the following

ubuntu/linux-image-4.4.0-274-lowlatency<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=14.04

All of the following

ubuntu/linux-image-aws<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=14.04

All of the following

ubuntu/linux-image-generic-lts-xenial<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=14.04

All of the following

ubuntu/linux-image-lowlatency-lts-xenial<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=14.04

All of the following

ubuntu/linux-image-virtual-lts-xenial<Ubuntu Pro

Ubuntu Pro

Ubuntu Ubuntu=14.04

ubuntu/linux-aws<4.4.0-1149.155

4.4.0-1149.155

ubuntu/linux-lts-xenial<4.4.0-274.308~14.04.1

4.4.0-274.308~14.04.1

ubuntu/linux<4.4.0-274.308

4.4.0-274.308

ubuntu/linux-aws<4.4.0-1187.202

4.4.0-1187.202

ubuntu/linux-kvm<4.4.0-1150.161

4.4.0-1150.161

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-image-4.4.0-1150-kvm to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.4.0-1187-aws to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.4.0-274-generic to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.4.0-274-lowlatency to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-aws to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-generic to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-generic-lts-xenial to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-kvm to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-lowlatency to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-lowlatency-lts-xenial to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-virtual to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-virtual-lts-xenial to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-image-4.4.0-1149-aws to a version that resolves this vulnerability.
Fixed in Ubuntu Pro
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.4.0-1149.155
Upgrade
Upgrade ubuntu/linux-lts-xenial to a version that resolves this vulnerability.
Fixed in 4.4.0-274.308~14.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 4.4.0-274.308
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.4.0-1187.202
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 4.4.0-1150.161
Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch USN-7863-1

Event History

Nov 6, 2025

Advisory Published

via Ubuntu·12:00 AM

Data Sourced

via Ubuntu·12:00 AM

DescriptionAffected Software

Advisory Published

via OSV·10:05 AM

Data Sourced

via OSV·10:05 AM

DescriptionAffected Software

Frequently Asked Questions

Which systems are exposed to the VMSCAPE issue?

The issue is relevant to systems running a userspace hypervisor on certain processors where untrusted guest VMs are present. A guest attacker could potentially expose sensitive information from the host operating system.

What access would an attacker need to exploit VMSCAPE?

The attacker would need to operate from within a guest virtual machine. The described impact is disclosure of sensitive information from the host OS.

What other kernel areas are covered by this update?

The update also corrects issues in the DMA engine, GPU drivers, HSI, Ethernet team driver, TTY drivers, Ext4, timers, DCCP, IPv6, NET/ROM, SCTP, and USB sound devices. The advisory states these issues could possibly be used to compromise the system.

USN-7863-1: Linux kernel vulnerabilities

Affected Software

Remediation

Event History

Child vulnerabilities

Frequently Asked Questions

Which systems are exposed to the VMSCAPE issue?

What access would an attacker need to exploit VMSCAPE?

What other kernel areas are covered by this update?

Company

Resources

Contact

Frequently Asked Questions

Which systems are exposed to the VMSCAPE issue?

What access would an attacker need to exploit VMSCAPE?

What other kernel areas are covered by this update?