AI-Found Linux Kernel Flaw Gives Local Users Root, and Can Break a Guest Out to the Host

Summary: A flaw in Linux's vhost subsystem, tracked as CVE-2026-74580 and named Vghost, lets a local user read and write kernel memory and escalate to root, and in one virtualization setup lets an untrusted guest write into the host's QEMU process and hijack it. Tencent Zhuque Lab, which found the bug, released a fix on August 3 and published a full write-up with working demos on October 12; the flaw affects kernels from 4.11 up to 7.2-rc4 and was reproduced on Ubuntu 26.04, RHEL 9.8, Amazon Linux 2023, Microsoft Azure Linux 3.0, and Oracle Linux 10.2.
What you should know: The bug sat in the kernel for about nine years because a 2017 change added a mapping cache and a 2020 change moved address checking to a later step, so a stale translation is trusted and the check never runs. On four of the five tested images the device node was world-readable at mode 0666, meaning any local user could reach it, and there is no interim workaround for the guest-to-host escape - only a patched kernel.

Read the original at The Hacker News ↗

Topics: Vulnerabilities & Patching
Mentions: CVE-2026-74580
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