CVE-2021-20221

MEDIUMNVD 6.06.0—
EchelonGraph scoreMEDIUM confidence

Score 6.0 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 6.0; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.0
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.0Exploit: NoneExposed: 0

A fix is available — apply it.

An out-of-bounds heap buffer access issue was found in the ARM Generic Interrupt Controller emulator of QEMU up to and including qemu 4.2.0on aarch64 platform. The issue occurs because while writing an interrupt ID to the controller memory area, it is not masked to be 4 bits wide. It may lead to the said issue while updating controller state fields and their subsequent processing. A privileged guest user may use this flaw to crash the QEMU process on the host resulting in DoS scenario.

CVSS v3
6.0
EG Score
6.0(medium)
EPSS
24.5%
KEV
Not listed

Published

May 13, 2021

Last Modified

November 21, 2024

References (10)

Vendor Advisories for CVE-2021-20221(2)

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

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuqemu-system-x86-xen (1:5.2+dfsg-9ubuntu3.1) @ hirsute2026-05-26ubuntu
redhatvirt:rhel-8040020210721215855.522a0ee42021-08-10redhat
redhatvirt-devel:8.2-8020120210603194525.863bb0db2021-06-22redhat
redhatvirt-devel:8.3-8030120210325145214.8f6a38fe2021-04-08redhat

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(2)

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 8× in last 7d / 44× 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.

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

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Frequently asked(5)

What is CVE-2021-20221?
CVE-2021-20221 is a medium vulnerability published on May 13, 2021. An out-of-bounds heap buffer access issue was found in the ARM Generic Interrupt Controller emulator of QEMU up to and including qemu 4.2.0on aarch64 platform. The issue occurs because while writing an interrupt ID to the controller memory area, it is not masked to be 4 bits wide. It may lead to…
When was CVE-2021-20221 disclosed?
CVE-2021-20221 was first published in the National Vulnerability Database on May 13, 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-2021-20221 actively exploited?
CVE-2021-20221 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 24.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-20221?
CVE-2021-20221 has a CVSS v3 base score of 6.0 (NVD).
How do I remediate CVE-2021-20221?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-20221, 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.

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