CVE-2026-63940

CRITICALPre-NVD 9.39.3—
EchelonGraph scoreMEDIUM confidence

Score 9.3 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-19. the CNA's CVSS baseline 9.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
Trending — 4 sources updated this week
9.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.3Exploit: None knownExposed: 0

A fix is available — apply it.

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.

CVSS v3
9.3
EG Score
9.3(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity93% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
8%
KEV
Not listed

Published

July 19, 2026

Last Modified

August 5, 2026

Advisory Details (4)

Auto-updated Aug 23, 2026
No patch confirmed yet.
generic

KVM: SEV: Ignore Port I/O requests of length '0' - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3988bd2723de407ae90fa7a6f6029b4e60238c58
generic

KVM: SEV: Ignore Port I/O requests of length '0' - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c30cde934c7813b4e3069765dac64ce3d31e34f2
generic

KVM: SEV: Ignore Port I/O requests of length '0' - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2254972d4d69e279ba4e87bf0968eb08ad0d3c92
generic

KVM: SEV: Ignore Port I/O requests of length '0' - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3b6035bc6bff20e89752ce4358bc4c9a9d5883f2

Vendor Advisories for CVE-2026-63940(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-oracle-7.0 (7.0.0-1008.8) @ resolute2026-08-30ubuntu
ubuntulinux-tools-azure-fde-7.0 (7.0.0-1009.9) @ resolute2026-08-30ubuntu
ubuntulinux-tools-raspi-realtime-7.0 (7.0.0-1015.15) @ resolute2026-08-30ubuntu
ubuntulinux-tools-nvidia-hwe-24.04-edge (7.0.0-1016.16) @ resolute2026-08-30ubuntu
ubuntulinux-tools-nvidia-hwe-26.04 (7.0.0-2016.16) @ resolute2026-08-30ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 7.2~rc5-1~exp1 (335 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.95-1~bpo12+1 (29 versions)6.12.95-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.0.9-1~bpo13+1 (138 versions)7.0.12-1—

All Vendor Advisories

(5)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 64× in last 7d / 375× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 452 total refreshes for this CVE.

  1. 2026-08-30 06:46 UTCVendor advisory
  2. 2026-08-30 06:46 UTCGHSA enrichment
  3. 2026-08-30 02:56 UTCEG score recompute
  4. 2026-08-30 02:56 UTCVendor advisory
  5. 2026-08-30 02:56 UTCGHSA enrichment
  6. 2026-08-30 01:22 UTCEPSS rescore
  7. 2026-08-28 21:42 UTCEPSS rescore
  8. 2026-08-28 01:43 UTCVendor advisory
  9. 2026-08-28 01:43 UTCGHSA enrichment
  10. 2026-08-27 21:23 UTCEG score recompute
  11. 2026-08-27 21:23 UTCVendor advisory
  12. 2026-08-27 21:23 UTCGHSA enrichment
  13. 2026-08-27 14:25 UTCEPSS rescore
  14. 2026-08-27 11:53 UTCVendor advisory
  15. 2026-08-27 11:53 UTCGHSA enrichment
  16. 2026-08-27 02:15 UTCVendor advisory
  17. 2026-08-27 02:15 UTCGHSA enrichment
  18. 2026-08-26 22:25 UTCEG score recompute
  19. 2026-08-26 22:25 UTCVendor advisory
  20. 2026-08-26 22:25 UTCGHSA enrichment
  21. 2026-08-26 14:46 UTCEPSS rescore
  22. 2026-08-26 11:42 UTCVendor advisory
  23. 2026-08-26 11:42 UTCGHSA enrichment
  24. 2026-08-26 07:24 UTCVendor advisory
  25. 2026-08-26 07:24 UTCGHSA enrichment
Show 75 more
  1. 2026-08-26 02:36 UTCVendor advisory
  2. 2026-08-26 02:36 UTCGHSA enrichment
  3. 2026-08-25 22:44 UTCVendor advisory
  4. 2026-08-25 22:44 UTCGHSA enrichment
  5. 2026-08-25 18:49 UTCGHSA enrichment
  6. 2026-08-25 14:37 UTCEG score recompute
  7. 2026-08-25 14:37 UTCVendor advisory
  8. 2026-08-25 14:37 UTCGHSA enrichment
  9. 2026-08-25 13:49 UTCEPSS rescore
  10. 2026-08-25 10:47 UTCVendor advisory
  11. 2026-08-25 10:47 UTCGHSA enrichment
  12. 2026-08-25 06:52 UTCVendor advisory
  13. 2026-08-25 06:52 UTCGHSA enrichment
  14. 2026-08-25 03:01 UTCVendor advisory
  15. 2026-08-25 03:01 UTCGHSA enrichment
  16. 2026-08-24 23:09 UTCVendor advisory
  17. 2026-08-24 23:09 UTCGHSA enrichment
  18. 2026-08-24 19:20 UTCVendor advisory
  19. 2026-08-24 19:20 UTCGHSA enrichment
  20. 2026-08-24 15:29 UTCEG score recompute
  21. 2026-08-24 15:29 UTCVendor advisory
  22. 2026-08-24 15:29 UTCGHSA enrichment
  23. 2026-08-24 11:38 UTCEG score recompute
  24. 2026-08-24 11:38 UTCVendor advisory
  25. 2026-08-24 11:38 UTCGHSA enrichment
  26. 2026-08-24 07:48 UTCVendor advisory
  27. 2026-08-24 07:48 UTCGHSA enrichment
  28. 2026-08-24 03:44 UTCVendor advisory
  29. 2026-08-24 03:44 UTCGHSA enrichment
  30. 2026-08-23 23:37 UTCVendor advisory
  31. 2026-08-23 23:37 UTCGHSA enrichment
  32. 2026-08-23 19:47 UTCVendor advisory
  33. 2026-08-23 19:47 UTCGHSA enrichment
  34. 2026-08-23 15:57 UTCVendor advisory
  35. 2026-08-23 15:57 UTCGHSA enrichment
  36. 2026-08-23 12:07 UTCVendor advisory
  37. 2026-08-23 12:07 UTCGHSA enrichment
  38. 2026-08-23 08:16 UTCVendor advisory
  39. 2026-08-23 08:16 UTCGHSA enrichment
  40. 2026-08-23 04:25 UTCVendor advisory
  41. 2026-08-23 04:24 UTCGHSA enrichment
  42. 2026-08-23 00:34 UTCEG score recompute
  43. 2026-08-23 00:34 UTCVendor advisory
  44. 2026-08-23 00:34 UTCGHSA enrichment
  45. 2026-08-23 00:19 UTCEPSS rescore
  46. 2026-08-22 20:43 UTCVendor advisory
  47. 2026-08-22 20:43 UTCGHSA enrichment
  48. 2026-08-22 16:53 UTCVendor advisory
  49. 2026-08-22 16:53 UTCGHSA enrichment
  50. 2026-08-22 13:02 UTCVendor advisory
  51. 2026-08-22 13:02 UTCGHSA enrichment
  52. 2026-08-22 09:12 UTCVendor advisory
  53. 2026-08-22 09:12 UTCGHSA enrichment
  54. 2026-08-22 05:21 UTCVendor advisory
  55. 2026-08-22 05:21 UTCGHSA enrichment
  56. 2026-08-22 01:31 UTCEG score recompute
  57. 2026-08-22 01:31 UTCVendor advisory
  58. 2026-08-22 01:31 UTCGHSA enrichment
  59. 2026-08-21 23:49 UTCEPSS rescore
  60. 2026-08-21 21:41 UTCVendor advisory
  61. 2026-08-21 21:41 UTCGHSA enrichment
  62. 2026-08-21 17:51 UTCVendor advisory
  63. 2026-08-21 17:51 UTCGHSA enrichment
  64. 2026-08-21 14:01 UTCVendor advisory
  65. 2026-08-21 14:00 UTCGHSA enrichment
  66. 2026-08-21 09:47 UTCVendor advisory
  67. 2026-08-21 09:47 UTCGHSA enrichment
  68. 2026-08-21 05:57 UTCVendor advisory
  69. 2026-08-21 05:57 UTCGHSA enrichment
  70. 2026-08-21 02:07 UTCVendor advisory
  71. 2026-08-21 02:07 UTCGHSA enrichment
  72. 2026-08-20 22:16 UTCVendor advisory
  73. 2026-08-20 22:16 UTCGHSA enrichment
  74. 2026-08-20 18:26 UTCVendor advisory
  75. 2026-08-20 18:26 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2026-63940?
CVE-2026-63940 is a critical vulnerability published on July 19, 2026. 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,…
When was CVE-2026-63940 disclosed?
CVE-2026-63940 was first published in the National Vulnerability Database on July 19, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63940 actively exploited?
CVE-2026-63940 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 91.9% of all scored CVEs.
What is the CVSS score of CVE-2026-63940?
CVE-2026-63940 has a CVSS v4.0 base score of 9.3 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-63940?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63940, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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