CVE-2021-4090

HIGHNVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2022-02-19. 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.

An out-of-bounds (OOB) memory write flaw was found in the NFSD in the Linux kernel. Missing sanity may lead to a write beyond bmval[bmlen-1] in nfsd4_decode_bitmap4 in fs/nfsd/nfs4xdr.c. In this flaw, a local attacker with user privilege may gain access to out-of-bounds memory, leading to a system integrity and confidentiality threat.

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
25%
KEV
Not listed

Published

February 18, 2022

Last Modified

August 25, 2026

Advisory Details (4)

Auto-updated Aug 25, 2026
No patch confirmed yet. Sources: redhat.
generic

NFSD: Fix exposure in nfsd4_decode_bitmap() - kernel/git/torvalds/linux.git - Linux kernel source tree

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c0019b7db1d7ac62c711cda6b357a659d46428fe
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20220318-0010/
generic

[PATCH v1] NFSD: Fix exposure in nfsd4_decode_bitmap() - Chuck Lever

https://lore.kernel.org/linux-nfs/163692036074.16710.5678362976688977923.stgit%40klimt.1015granger.net/
redhat

2025101 – (CVE-2021-4090) CVE-2021-4090 kernel: Overflow of bmval[bmlen-1] in nfsd4_decode_bitmap function

https://bugzilla.redhat.com/show_bug.cgi?id=2025101

Vendor Advisories for CVE-2021-4090(1)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-oem-5.14-tools-5.14.0-1018 (5.14.0-1018.19) @ focal2026-08-25ubuntu
ubuntulinux-image-lowlatency (5.13.0.28.38) @ impish2026-08-25ubuntu
ubuntulinux-image-unsigned-5.13.0-1010-intel (5.13.0-1010.10) @ focal2026-08-25ubuntu

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

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux—5.15.5-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux—5.15.5-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux—5.15.5-1—

Weakness Classification(1)

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

All Vendor Advisories

(4)

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 8× in last 7d / 28× 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 206 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-4090?
CVE-2021-4090 is a high vulnerability published on February 18, 2022. An out-of-bounds (OOB) memory write flaw was found in the NFSD in the Linux kernel. Missing sanity may lead to a write beyond bmval[bmlen-1] in nfsd4decodebitmap4 in fs/nfsd/nfs4xdr.c. In this flaw, a local attacker with user privilege may gain access to out-of-bounds memory, leading to a system…
When was CVE-2021-4090 disclosed?
CVE-2021-4090 was first published in the National Vulnerability Database on February 18, 2022, with the most recent update on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-4090 actively exploited?
CVE-2021-4090 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 75.5% of all scored CVEs.
What is the CVSS score of CVE-2021-4090?
CVE-2021-4090 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2021-4090?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-4090, 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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