CVE-2021-22543

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.8 under NVD CVSS v3. EPSS exploit probability: 0.7%, top 52% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this week
7.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.8Exploit: NoneExposed: 0

A fix is available — apply it.

An issue was discovered in Linux: KVM through Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users with the ability to start and control a VM to read/write random pages of memory and can result in local privilege escalation.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: 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
Severity78% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
47.8%
KEV
Not listed

Published

May 26, 2021

Last Modified

November 21, 2024

References (14)

Vendor Advisories for CVE-2021-22543(18)

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

Patch Availability(24)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-image-lowlatency (5.11.0.34.36) @ hirsute2026-05-26ubuntu
ubuntulinux-modules-5.4.0-84-lowlatency (5.4.0-84.94) @ focal2026-05-26ubuntu
ubuntulinux-cloud-tools-generic-hwe-18.04-edge (5.4.0.84.94~18.04.75) @ bionic2026-05-26ubuntu
ubuntulinux-image-raspi2-hwe-18.04 (5.4.0.1043.78) @ focal2026-05-26ubuntu
ubuntulinux-virtual-hwe-16.04-edge (4.15.0.159.152) @ xenial2026-05-26ubuntu
ubuntulinux-image-raspi2 (4.15.0.1096.94) @ bionic2026-05-26ubuntu
ubuntulinux-azure-5.8-headers-5.8.0-1043 (5.8.0-1043.46~20.04.1) @ focal2026-05-26ubuntu
ubuntulinux-oem-20.04b (5.10.0.1049.51) @ focal2026-05-26ubuntu
redhatkernel-0:2.6.32-754.48.1.el62022-07-19redhat
redhatkernel-0:3.10.0-1062.59.1.el72021-10-26redhat
redhatkpatch-patch2021-10-26redhat
redhatredhat-virtualization-host-0:4.3.19-20211013.0.el7_92021-10-20redhat
redhatkernel-0:3.10.0-327.101.1.el72021-10-12redhat
redhatkernel-0:3.10.0-514.93.1.el72021-10-12redhat
redhatkernel-0:3.10.0-1160.45.1.el72021-10-12redhat
redhatkernel-rt-0:3.10.0-1160.45.1.rt56.1185.el72021-10-12redhat
redhatkernel-0:3.10.0-957.84.1.el72021-10-12redhat
redhatkernel-0:3.10.0-693.94.1.el72021-10-05redhat
redhatkernel-0:4.18.0-193.64.1.el8_22021-08-31redhat
redhatkernel-rt-0:4.18.0-193.64.1.rt13.115.el8_22021-08-31redhat
redhatredhat-virtualization-host-0:4.4.7-20210804.0.el8_42021-08-19redhat
redhatkernel-0:4.18.0-147.52.1.el8_12021-08-17redhat
redhatkernel-rt-0:4.18.0-305.12.1.rt7.84.el8_42021-08-10redhat
redhatkernel-0:4.18.0-305.12.1.el8_42021-08-10redhat

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.

Weakness Classification(1)

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

Additional Vendor Advisories

(7)

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 11× in last 7d / 49× 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 103 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-22543?
CVE-2021-22543 is a high vulnerability published on May 26, 2021. An issue was discovered in Linux: KVM through Improper handling of VMIO|VMPFNMAP vmas in KVM can bypass RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users with the ability to start and control a VM to read/write random pages of memory and can…
When was CVE-2021-22543 disclosed?
CVE-2021-22543 was first published in the National Vulnerability Database on May 26, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-22543 actively exploited?
CVE-2021-22543 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 47.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-22543?
CVE-2021-22543 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2021-22543?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-22543, 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

Explore the affected products and dependency analysis for CVE-2021-22543

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