CVE-2021-3929

HIGHNVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2022-08-26. NVD baseline CVSS 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.2Exploit: Elevated riskExposed: 0

A fix is available — apply it.

A DMA reentrancy issue was found in the NVM Express Controller (NVME) emulation in QEMU. This CVE is similar to CVE-2021-3750 and, just like it, when the reentrancy write triggers the reset function nvme_ctrl_reset(), data structs will be freed leading to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition or, potentially, executing arbitrary code within the context of the QEMU process on the host.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
57(Track)
EG Risk 57/100SSVC: 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
Severity82% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
50%
KEV
Not listed

Published

August 25, 2022

Last Modified

February 28, 2025

Advisory Details (6)

Auto-updated Sep 8, 2026
Patch available. Sources: redhat.
generic

Fix DMA MMIO reentrancy issues (#556) · Issues · QEMU / QEMU · GitLab

https://gitlab.com/qemu-project/qemu/-/issues/556
generic

hw/nvme: fix CVE-2021-3929 (736b0164) · Commits · QEMU / QEMU · GitLab

https://gitlab.com/qemu-project/qemu/-/commit/736b01642d85be832385
redhat Patch Available

2020298 – (CVE-2021-3929) CVE-2021-3929 QEMU: nvme: DMA reentrancy issue leads to use-after-free

https://bugzilla.redhat.com/show_bug.cgi?id=2020298
redhat Patch Available

CVE-2021-3929 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2021-3929
generic

[SECURITY] Fedora 36 Update: qemu-6.2.0-15.fc36 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XHNN7QJCEQH7AQG5AQP2GEFAQE6K635I/
generic

nvme: DMA reentrancy issue leads to use-after-free (CVE-2021-3929) (#782) · Issues · QEMU / QEMU · GitLab

https://gitlab.com/qemu-project/qemu/-/issues/782

Vendor Advisories for CVE-2021-3929(1)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuqemu-system-x86-xen (1:6.2+dfsg-2ubuntu6.2) @ jammy2026-05-25ubuntu

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
qemu1:10.0.0+ds-1 ... 1:9.2.2+ds-1~bpo12+1 (225 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
qemu—1:7.0+dfsg-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
qemu—1:7.0+dfsg-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
qemu—1:7.0+dfsg-1—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

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 9× 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 174 total refreshes for this CVE.

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

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCQiuhaoLi/CVE-2021-3929-3947
    First seen May 13, 2022

    Recursive MMIO VM Escape PoC

    Open source ↗

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-3929?
CVE-2021-3929 is a high vulnerability published on August 25, 2022. A DMA reentrancy issue was found in the NVM Express Controller (NVME) emulation in QEMU. This CVE is similar to CVE-2021-3750 and, just like it, when the reentrancy write triggers the reset function nvmectrlreset(), data structs will be freed leading to a use-after-free issue. A malicious guest…
When was CVE-2021-3929 disclosed?
CVE-2021-3929 was first published in the National Vulnerability Database on August 25, 2022, with the most recent update on February 28, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-3929 actively exploited?
CVE-2021-3929 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 50.2% of all scored CVEs.
What is the CVSS score of CVE-2021-3929?
CVE-2021-3929 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2021-3929?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3929, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-3929

Explore →

Is Your Infrastructure Affected by CVE-2021-3929?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs