CVE-2021-47400

MEDIUMNVD 5.55.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.3% (17th percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 4.0 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2024-05-21) is not newer than that change (2026-08-05), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2021-34405 (ENISA EUVD) · GHSA-wr76-p7r7-8vjv (GitHub Security Advisories)Source: ENISA EUVD

5.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

net: hns3: do not allow call hns3_nic_net_open repeatedly

hns3_nic_net_open() is not allowed to called repeatly, but there is no checking for this. When doing device reset and setup tc concurrently, there is a small oppotunity to call hns3_nic_net_open repeatedly, and cause kernel bug by calling napi_enable twice.

The calltrace information is like below: [ 3078.222780] ------------[ cut here ]------------ [ 3078.230255] kernel BUG at net/core/dev.c:6991! [ 3078.236224] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 3078.243431] Modules linked in: hns3 hclgevf hclge hnae3 vfio_iommu_type1 vfio_pci vfio_virqfd vfio pv680_mii(O) [ 3078.258880] CPU: 0 PID: 295 Comm: kworker/u8:5 Tainted: G O 5.14.0-rc4+ #1 [ 3078.269102] Hardware name: , BIOS KpxxxFPGA 1P B600 V181 08/12/2021 [ 3078.276801] Workqueue: hclge hclge_service_task [hclge] [ 3078.288774] pstate: 60400009 (nZCv daif +PAN -UAO -TCO BTYPE=--) [ 3078.296168] pc : napi_enable+0x80/0x84 tc qdisc sho[w 3d0e7v8 .e3t0h218 79] lr : hns3_nic_net_open+0x138/0x510 [hns3]

[ 3078.314771] sp : ffff8000108abb20 [ 3078.319099] x29: ffff8000108abb20 x28: 0000000000000000 x27: ffff0820a8490300 [ 3078.329121] x26: 0000000000000001 x25: ffff08209cfc6200 x24: 0000000000000000 [ 3078.339044] x23: ffff0820a8490300 x22: ffff08209cd76000 x21: ffff0820abfe3880 [ 3078.349018] x20: 0000000000000000 x19: ffff08209cd76900 x18: 0000000000000000 [ 3078.358620] x17: 0000000000000000 x16: ffffc816e1727a50 x15: 0000ffff8f4ff930 [ 3078.368895] x14: 0000000000000000 x13: 0000000000000000 x12: 0000259e9dbeb6b4 [ 3078.377987] x11: 0096a8f7e764eb40 x10: 634615ad28d3eab5 x9 : ffffc816ad8885b8 [ 3078.387091] x8 : ffff08209cfc6fb8 x7 : ffff0820ac0da058 x6 : ffff0820a8490344 [ 3078.396356] x5 : 0000000000000140 x4 : 0000000000000003 x3 : ffff08209cd76938 [ 3078.405365] x2 : 0000000000000000 x1 : 0000000000000010 x0 : ffff0820abfe38a0 [ 3078.414657] Call trace: [ 3078.418517] napi_enable+0x80/0x84 [ 3078.424626] hns3_reset_notify_up_enet+0x78/0xd0 [hns3] [ 3078.433469] hns3_reset_notify+0x64/0x80 [hns3] [ 3078.441430] hclge_notify_client+0x68/0xb0 [hclge] [ 3078.450511] hclge_reset_rebuild+0x524/0x884 [hclge] [ 3078.458879] hclge_reset_service_task+0x3c4/0x680 [hclge] [ 3078.467470] hclge_service_task+0xb0/0xb54 [hclge] [ 3078.475675] process_one_work+0x1dc/0x48c [ 3078.481888] worker_thread+0x15c/0x464 [ 3078.487104] kthread+0x160/0x170 [ 3078.492479] ret_from_fork+0x10/0x18 [ 3078.498785] Code: c8027c81 35ffffa2 d50323bf d65f03c0 (d4210000) [ 3078.506889] ---[ end trace 8ebe0340a1b0fb44 ]---

Once hns3_nic_net_open() is excute success, the flag HNS3_NIC_STATE_DOWN will be cleared. So add checking for this flag, directly return when HNS3_NIC_STATE_DOWN is no set.

CVSS v3
5.5
EG Score
5.5MEDIUMmedium confidence
EG Risk
25
EG Risk 25/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity55% × 45%
Impact severity (EG Severity): CVSS 5.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
17th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.

EG Severity
5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-25). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

May 21, 2024

Last Modified

August 5, 2026

References (4)

Vendor Advisories for CVE-2021-47400(3)

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 / EcosystemFix (by version range) / PatchReleasedSource
redhatkernel-0:5.14.0-427.24.1.el9_42024-07-08redhat
redhatkernel-0:5.14.0-284.71.1.el9_22024-06-26redhat
redhatkernel-rt-0:5.14.0-284.71.1.rt14.356.el9_22024-06-26redhat

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 rangeFix by version rangeDependents
linux5.10.46-4, 5.10.46-5, 5.10.70-1, 5.10.70-1~bpo10+1
  • every version up to 5.10.84-1: fixed in 5.10.84-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.14.12-1: fixed in 5.14.12-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.14.12-1: fixed in 5.14.12-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.14.12-1: fixed in 5.14.12-1
—

Data Freshness Timeline

(refreshed 7× in last 7d / 39× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 97 of 219 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 3 repeat rows among the latest 100 are merged into the row they repeat. The 122 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-03 16:38 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  2. 2026-11-02 16:38 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  3. 2026-11-01 16:30 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  4. 2026-10-31 16:29 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  5. 2026-10-30 16:30 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  6. 2026-10-29 16:29 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  7. 2026-10-28 16:28 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  8. 2026-10-27 16:28 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  9. 2026-10-26 16:28 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  10. 2026-10-25 18:18 UTCEG score recompute
  11. 2026-10-25 16:29 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  12. 2026-10-24 21:44 UTCEG score recompute
  13. 2026-10-24 21:44 UTCVendor advisory
  14. 2026-10-24 21:44 UTCGHSA enrichmentGHSA-wr76-p7r7-8vjv · GitHub CVSS 4.0
  15. 2026-10-24 16:29 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  16. 2026-10-23 16:28 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  17. 2026-10-22 16:29 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  18. 2026-10-21 16:28 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  19. 2026-10-20 16:28 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  20. 2026-10-19 16:28 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  21. 2026-10-19 12:25 UTCOSV refresh
  22. 2026-10-18 16:28 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  23. 2026-10-18 08:49 UTCEG score recompute
  24. 2026-10-17 16:29 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  25. 2026-10-16 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
Show 72 more
  1. 2026-10-15 16:28 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  2. 2026-10-14 16:29 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  3. 2026-10-13 16:28 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  4. 2026-10-12 19:05 UTCEG score recompute
  5. 2026-10-12 16:30 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  6. 2026-10-11 23:31 UTCEG score recompute
  7. 2026-10-11 13:44 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  8. 2026-10-10 19:56 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  9. 2026-10-09 20:04 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  10. 2026-10-08 16:40 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  11. 2026-10-07 23:45 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  12. 2026-10-06 15:14 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  13. 2026-10-05 17:40 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  14. 2026-10-04 23:19 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  15. 2026-10-03 14:22 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  16. 2026-10-02 16:23 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  17. 2026-09-30 15:45 UTCEG score recompute
  18. 2026-09-30 15:00 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  19. 2026-09-29 15:15 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  20. 2026-09-28 13:47 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  21. 2026-09-26 19:33 UTCOSV refresh
  22. 2026-09-26 15:54 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  23. 2026-09-26 00:21 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  24. 2026-09-24 14:00 UTCEPSS rescoreEPSS 0.3% · 15th percentile
  25. 2026-09-23 13:45 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  26. 2026-09-22 14:44 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  27. 2026-09-21 20:28 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  28. 2026-09-20 20:13 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  29. 2026-09-19 15:38 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  30. 2026-09-18 19:24 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  31. 2026-09-17 19:23 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  32. 2026-09-16 14:05 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  33. 2026-09-15 03:06 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  34. 2026-09-12 14:57 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  35. 2026-09-11 14:49 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  36. 2026-09-11 09:33 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  37. 2026-09-08 21:57 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  38. 2026-09-07 15:58 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  39. 2026-09-07 05:18 UTCOSV refresh
  40. 2026-09-06 13:45 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  41. 2026-09-05 15:25 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  42. 2026-09-04 13:57 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  43. 2026-09-04 05:03 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  44. 2026-09-02 14:09 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  45. 2026-09-01 13:51 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  46. 2026-08-30 19:14 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  47. 2026-08-30 01:19 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  48. 2026-08-28 21:38 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  49. 2026-08-27 14:22 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  50. 2026-08-26 14:43 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  51. 2026-08-25 13:46 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  52. 2026-08-24 14:13 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  53. 2026-08-21 23:46 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  54. 2026-08-20 22:52 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  55. 2026-08-20 15:01 UTCOSV refresh
  56. 2026-08-19 17:01 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  57. 2026-08-18 13:45 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  58. 2026-08-17 13:44 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  59. 2026-08-16 14:53 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  60. 2026-08-16 02:11 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  61. 2026-08-15 01:27 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  62. 2026-08-13 21:57 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  63. 2026-08-12 13:48 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  64. 2026-08-11 13:38 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  65. 2026-08-09 13:44 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  66. 2026-08-08 16:34 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  67. 2026-08-07 16:24 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  68. 2026-08-06 13:44 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  69. 2026-08-05 19:15 UTCEPSS rescoreEPSS 0.3% · 16th percentile
  70. 2026-08-05 09:40 UTCEG score recompute
  71. 2026-08-05 09:40 UTCVendor advisory
  72. 2026-08-05 09:40 UTCGHSA enrichmentGHSA-wr76-p7r7-8vjv · GitHub CVSS 4.0

Related CVEs(same vendor)

Frequently asked(5)

What is CVE-2021-47400?
CVE-2021-47400 is a medium-severity vulnerability; its CVE record was published on May 21, 2024. In the Linux kernel, the following vulnerability has been resolved: net: hns3: do not allow call hns3_nic_net_open repeatedly hns3_nic_net_open() is not allowed to called repeatly, but there is no checking for this. When doing device reset and setup tc concurrently, there is a small oppotunity to…
When was the CVE record for CVE-2021-47400 published?
The CVE record for CVE-2021-47400 was published on May 21, 2024. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of August 5, 2026; the record at its source may have been updated since.
Is CVE-2021-47400 actively exploited?
CVE-2021-47400 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (17th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-47400?
CVE-2021-47400 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2021-47400?
A fix for CVE-2021-47400 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2021-47400 are linked in the Vendor Advisories panel on this page.

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