What is CVE-2026-63940?

CVE-2026-63940 is a critical-severity vulnerability in Linux. CVSS score: 9.3/10. Published 2026-07-19.

How severe is CVE-2026-63940?

Critical severity. CVSS v3 base score is 9.3 out of 10.

Vulnerability in Linux

CVE-2026-63940

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Ignore Port I/O requests of length '0' Explicitly ignore Port I/O requests of length '0' (or count '0'), so that setting up the software scratch area (and othe…

EPSS: 0.002 (10.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Linux — versions 291bd20d5d88814a73d43b55b9428feab2f28094, 5.11, 0

References

416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67
416baaa9-dc9f-4396-8d5f-8c081fb06d67

Frequently asked questions

What is CVE-2026-63940?: CVE-2026-63940 is a critical-severity vulnerability in Linux. CVSS score: 9.3/10. Published 2026-07-19.
How severe is CVE-2026-63940?: Critical severity. CVSS v3 base score is 9.3 out of 10.