CVE-2026-46076

What it is

In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1 Explicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want to intercept VMMCALL, nested_svm_l2_tlb_flush_enabled() is true, and the hypercall is something other than one of the supported Hyper-V hypercalls. When all of the above conditions are met, KVM will intercept VMMCALL but never forward it to L1, i.e. will let L2 make hypercalls as if it were L1. The TLFS says a whole lot of nothing about this scenario, so go with the architectural behavior, which says that VMMCALL #UDs if it's not intercepted. Opportunistically do a 2-for-1 stub trade by stub-ifying the new API instead of the helpers it uses. The last remaining "single" stub will soon be dropped as well. [sean: rewrite changelog and comment, tag for stable, remove defunct stubs]

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-27 14:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-21 13:19 UTC Last updatedMost recent change to the record

Details

Published

2026-05-27 14:17 UTC

Last modified

2026-10-21 13:19 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-863 · Incorrect authorization

Record status

Undergoing Analysis

Affected

• Linux Kernel < 6.12.86
• Linux Kernel < 6.18.27
• Linux Kernel < 7.0.4

Attack profile CVSS 3.1 · 7.9

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

High