PT-2026-61123 · Linux · Linux Kernel

CVE-2026-63807 · Published 2026-07-19 · Updated 2026-07-20

Positive Technologies (AI Summary)

CVSS v3.1

8.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An out-of-bounds access issue exists in the KVM x86 MMU when recovering hugepages in the shadow MMU. The system fails to verify if the base guest frame number (gfn) of the shadow page is contained within the target memslot before querying the maximum mapping level. This can occur if a guest creates a hugepage mapping that extends below the bounds of a memslot, leading to an out-of-bounds access to the lpage info of the slot, which typically results in a host page fault. The issue is triggered during the hugepage recovery flow when KVM replaces a direct shadow page with a hugepage after a 4KiB mapping restriction is lifted.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Related Identifiers

CVE-2026-63807

Affected Products

Linux Kernel

References · 10

• https://nvd.nist.gov/vuln/detail/CVE-2026-63807 · Security Note
• https://git.kernel.org/stable/c/7b52008023b7facf40fba3ebe92449bda8ea53b9 · Note
• https://twitter.com/windowsforum/status/2079129224225370609 · Twitter Post
• https://git.kernel.org/stable/c/b2ae3245ea44dccaa9af676b6747476951883318 · Note
• https://git.kernel.org/stable/c/5cab1c989f938f5e1b9a0de66486f1fc2c28479b · Note
• https://twitter.com/VulmonFeeds/status/2078899713521185030 · Twitter Post
• https://git.kernel.org/stable/c/48b91ed7e22bb82571c34f8b80b6ecdc90a6fab8 · Note
• https://git.kernel.org/stable/c/18587f9831612e24cd8f24be1ec15478feff7abc · Note
• https://git.kernel.org/stable/c/c5c29b3c268332afe67d598a034c58344540ed92 · Note
• https://git.kernel.org/stable/c/ef057cbf825e03b63f6edf5980f96abf3c53089d · Note