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 other code) doesn't have to worry about underflowing the length, and to allow for WARNing on trying to configure the scratch area with len==0.

Package Linux Kernel
Published 2026-07-19
Last modified 2026-07-19
Patch available
Yes

Affected versions

Linux kernel versions 5.11 and later are affected. Fixed in 6.12.95, 6.18.35, 7.0.12, 7.1 and their respective stable series.

Affected from
≥ 5.11
Fixed in
✓ 6.12.95 6.12.x ✓ 6.18.35 6.18.x ✓ 7.0.12 7.0.x ✓ 7.1

References

4 total

Frequently asked questions

  • What is CVE-2026-63940?

    CVE-2026-63940 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.11 onward and has been patched in 6.12.95, 6.18.35, 7.0.12 and others. CVE-2026-63940 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • Is there a patch available for CVE-2026-63940?

    Yes — CVE-2026-63940 has been patched. Fixed versions include 6.12.95, 6.18.35, 7.0.12 and others. If you are running Linux kernel 5.11 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-63940 actively exploited?

    No — CVE-2026-63940 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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