CVE-2021-3501

HIGHNVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

A fix is available — apply it.

A flaw was found in the Linux kernel in versions before 5.12. The value of internal.ndata, in the KVM API, is mapped to an array index, which can be updated by a user process at anytime which could lead to an out-of-bounds write. The highest threat from this vulnerability is to data integrity and system availability.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity71% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
31%
KEV
Not listed

Published

May 6, 2021

Last Modified

August 5, 2026

Advisory Details (3)

Auto-updated Aug 5, 2026
Patch available. Sources: redhat.
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20210618-0008/
generic

KVM: VMX: Don't use vcpu->run->internal.ndata as an array index - kernel/git/torvalds/linux.git - Linux kernel source tree

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=04c4f2ee3f68c9a4bf1653d15f1a9a435ae33f7a
redhat Patch Available

1950136 – (CVE-2021-3501) CVE-2021-3501 kernel: userspace applications can misuse the KVM API to cause a write of 16 bytes at an offset up to 32 GB from vcpu->run

Affected: Red Hat Enterprise Linux 8 starting with RHEL-8.4.0 and onward kernel version.

https://bugzilla.redhat.com/show_bug.cgi?id=1950136

Vendor Advisories for CVE-2021-3501(5)

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

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-image-virtual-hwe-20.04-edge (5.11.0.18.19) @ hirsute2026-05-26ubuntu
ubuntulinux-image-oem-20.04b (5.10.0.1029.30) @ focal2026-05-26ubuntu
redhatredhat-virtualization-host-0:4.4.6-20210615.0.el8_42021-06-22redhat
redhatkpatch-patch2021-06-01redhat
redhatkernel-0:4.18.0-305.3.1.el8_42021-06-01redhat
redhatkernel-rt-0:4.18.0-305.3.1.rt7.75.el8_42021-06-01redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.38-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.38-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.38-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux—5.10.38-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(3)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 6× in last 7d / 31× 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 169 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-3501?
CVE-2021-3501 is a high vulnerability published on May 6, 2021. A flaw was found in the Linux kernel in versions before 5.12. The value of internal.ndata, in the KVM API, is mapped to an array index, which can be updated by a user process at anytime which could lead to an out-of-bounds write. The highest threat from this vulnerability is to data integrity and…
When was CVE-2021-3501 disclosed?
CVE-2021-3501 was first published in the National Vulnerability Database on May 6, 2021, 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-2021-3501 actively exploited?
CVE-2021-3501 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 68.7% of all scored CVEs.
What is the CVSS score of CVE-2021-3501?
CVE-2021-3501 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2021-3501?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3501, 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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