CVE-2026-63937 | In the Linux kernel, the following vulnerability has been re… | CVSS 8.8 HIGH

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer Use READ_ONCE() when reading entries/indices from the guest-accessible Page State Change buffer to defend against TOCTOU bugs. Don't bother with READ_ONCE()/WRITE_ONCE() for cases where KVM is writing (and not consuming the result!), as the guest isn't supposed to touch the buffer while it's being processed. I.e. using READ_ONCE() is all about protecting against misbehaving guests.

Metadata

CVE ID: CVE-2026-63937
State: PUBLISHED
Assigner: Linux
Reserved: 2026-07-19 07:54 UTC
Published: 2026-07-19 14:55 UTC
Last updated: 2026-07-20 13:41 UTC
Vendor / Product: Linux / Linux
Sources: cve.org · NVD

Severity & Metrics

8.8 HIGH CVSS 3.1

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products (2)

Vendor	Product	Platform	Versions
Linux	Linux	—	9b54e248d2644be71cb394eb85f31ad99e023a05 < bd232801ef1d1fd985d2d4ca3cd1d888303ca86f, 9b54e248d2644be71cb394eb85f31ad99e023a05 < b1dfaa6f7a957726a6800135be3659fbe4bbf2a4, 9b54e248d2644be71cb394eb85f31ad99e023a05 < edbbe88f83b524434974e84808d3093199d67c24, 9b54e248d2644be71cb394eb85f31ad99e023a05 < c8cc238093ca6c99267032f6cfe78f59389f3157
Linux	Linux	—	6.11, 0 < 6.11, 6.12.93 ≤ 6.12., 6.18.35 ≤ 6.18. …

CVSS scores (1)

Score	Severity	Version	Source	Vector
8.8	HIGH	3.1	cna	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References (4)