NEWS

NEWS

Article from Issue 310/2026
Author(s): , Author(s):

In the news: New Linux Flaw Lets Attackers Escape VMs; Three Lines of Code Improve Linux Storage Performance; AUR Hit Again with Malicious Packages; Alpine Linux 3.24 Features Fresh Desktops and a Newer Kernel; EU Open Source Strategy Plays Key Role in Tech Sovereignty Package; Linux Foundation Report Indicates AI Driving Tech Hiring; and United Nations Open Source Portal Goes Live.

New Linux Flaw Lets Attackers Escape VMs

Security researcher Hyunwoo Kim, who goes by the name V4bel online, discovered the vulnerability and released an abstract on GitHub (https://github.com/V4bel/Januscape) about it stating, "Januscape is a use-after-free vulnerability in the shadow MMU emulation of KVM/x86." Kim continues, "It can trigger the bug with guest-side actions alone to corrupt the host kernel's shadow page, and it can threaten the guest-host isolation of KVM/x86 hosts that accept untrusted guests and expose nested virtualization, particularly multi-tenant x86 public clouds (GCP, AWS, etc.)." In the abstract, Kim also demonstrates how this attack can be made via proof-of-concept to trigger a kernel panic.

Kim also claims that Januscape was the basis for the zero-day exploit in Google kvmCTF (https://security.googleblog.com/2024/06/virtual-escape-real-reward-introducing.html), which (according to Google) "is a vulnerability reward program designed to help identify and address vulnerabilities in the Kernel-based Virtual Machine (KVM) hypervisor. It offers a lab environment where participants can log in and utilize their exploits to obtain flags."

Januscape is the first guest-to-host exploit that can be triggered on both AMD and Intel architectures, and it could allow an attacker to do things like panic the kernel on the host and take down every tenant VM.

[...]

Use Express-Checkout link below to read the full article (PDF).

Buy Linux Magazine

Related content

comments powered by Disqus
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters

Support Our Work

Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

Learn More

News