CVE-2021-3739

HIGHNVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.1 under NVD CVSS v3. EPSS exploit probability: 0.6%, top 53% 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
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.1Exploit: None knownExposed: 0

A fix is available — apply it.

A NULL pointer dereference flaw was found in the btrfs_rm_device function in fs/btrfs/volumes.c in the Linux Kernel, where triggering the bug requires ‘CAP_SYS_ADMIN’. This flaw allows a local attacker to crash the system or leak kernel internal information. The highest threat from this vulnerability is to 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%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
48%
KEV
Not listed

Published

March 10, 2022

Last Modified

September 1, 2026

Advisory Details (5)

Auto-updated Sep 1, 2026
Patch available. Sources: redhat, github_commit.
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20220407-0006/
github_commit

commit e4571b8c5e9f (torvalds/linux)

Fix landed in torvalds/linux commit e4571b8c5e9f — awaiting tagged release

https://github.com/torvalds/linux/commit/e4571b8c5e9ffa1e85c0c671995bd4dcc5c75091
generic

btrfs: fix NULL pointer dereference when deleting device by invalid id - kernel/git/torvalds/linux.git - Linux kernel source tree

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e4571b8c5e9ffa1e85c0c671995bd4dcc5c75091
redhat Patch Available

1997958 – (CVE-2021-3739) CVE-2021-3739 kernel: null-ptr-dereference bug in btrfs_rm_device in fs/btrfs/volumes.c

https://bugzilla.redhat.com/show_bug.cgi?id=1997958
generic

oss-security - Linux kernel: fs/btrfs: null-ptr-dereference bug in btrfs_rm_device in fs/btrfs/volumes.c

https://www.openwall.com/lists/oss-security/2021/08/25/3

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-headers-5.11.0-1021-raspi (5.11.0-1021.22) @ hirsute2026-05-26ubuntu
ubuntulinux-oem-5.13-tools-5.13.0-1017 (5.13.0-1017.21) @ focal2026-05-26ubuntu
ubuntulinux-tools-oem-20.04-edge (5.10.0.1050.52) @ focal2026-05-26ubuntu
ubuntulinux-oem-tools-host (5.4.0.90.94) @ focal2026-05-26ubuntu
ubuntulinux-image-raspi2-hwe-18.04 (5.4.0.1046.81) @ focal2026-05-26ubuntu

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
linux5.10.46-45.10.46-5—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux—5.14.6-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux—5.14.6-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux—5.14.6-1—

Weakness Classification(1)

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

All Vendor Advisories

(6)

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 / 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. 2026-09-20 20:13 UTCEPSS rescore
  2. 2026-09-20 18:14 UTCOSV refresh
  3. 2026-09-19 15:38 UTCEPSS rescore
  4. 2026-09-18 19:23 UTCEPSS rescore
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  19. 2026-09-01 18:09 UTCEG score recompute
  20. 2026-09-01 18:09 UTCVendor advisory
  21. 2026-09-01 13:50 UTCEPSS rescore
  22. 2026-09-01 03:33 UTCEPSS rescore
  23. 2026-08-30 19:14 UTCEPSS rescore
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  1. 2026-08-28 21:37 UTCEPSS rescore
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  10. 2026-08-19 17:01 UTCEPSS rescore
  11. 2026-08-19 06:29 UTCOSV refresh
  12. 2026-08-18 13:45 UTCEPSS rescore
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  14. 2026-08-16 14:53 UTCEPSS rescore
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  21. 2026-08-08 16:33 UTCEPSS rescore
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  23. 2026-08-06 13:44 UTCEPSS rescore
  24. 2026-08-05 19:14 UTCEPSS rescore
  25. 2026-08-04 10:34 UTCEPSS rescore
  26. 2026-08-04 01:57 UTCOSV refresh
  27. 2026-08-03 10:33 UTCEPSS rescore
  28. 2026-08-02 02:24 UTCEPSS rescore
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  30. 2026-07-30 16:25 UTCEPSS rescore
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  37. 2026-07-23 14:16 UTCEPSS rescore
  38. 2026-07-23 02:03 UTCEG score recompute
  39. 2026-07-22 22:49 UTCEG score recompute
  40. 2026-07-22 14:06 UTCEPSS rescore
  41. 2026-07-21 15:22 UTCEPSS rescore
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  43. 2026-07-20 17:05 UTCEPSS rescore
  44. 2026-07-19 14:29 UTCEPSS rescore
  45. 2026-07-19 02:27 UTCEPSS rescore
  46. 2026-07-18 10:02 UTCEPSS rescore
  47. 2026-07-18 10:02 UTCEPSS rescore
  48. 2026-07-17 20:59 UTCOSV refresh
  49. 2026-07-16 17:00 UTCEPSS rescore
  50. 2026-07-16 17:00 UTCEPSS rescore
  51. 2026-07-15 16:55 UTCEPSS rescore
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  53. 2026-07-15 01:58 UTCEPSS rescore
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  63. 2026-07-07 13:43 UTCEPSS rescore
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  68. 2026-07-05 02:28 UTCEPSS rescore
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  70. 2026-07-04 06:29 UTCEPSS rescore
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  72. 2026-07-02 16:57 UTCEPSS rescore
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  74. 2026-06-30 23:20 UTCEPSS rescore
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Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-3739?
CVE-2021-3739 is a high vulnerability published on March 10, 2022. A NULL pointer dereference flaw was found in the btrfsrmdevice function in fs/btrfs/volumes.c in the Linux Kernel, where triggering the bug requires ‘CAPSYSADMIN’. This flaw allows a local attacker to crash the system or leak kernel internal information. The highest threat from this vulnerability…
When was CVE-2021-3739 disclosed?
CVE-2021-3739 was first published in the National Vulnerability Database on March 10, 2022, with the most recent update on September 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-3739 actively exploited?
CVE-2021-3739 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 51.9% of all scored CVEs.
What is the CVSS score of CVE-2021-3739?
CVE-2021-3739 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2021-3739?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3739, 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-2021-3739

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