CVE-2026-31437

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-04-22. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

netfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry

When a write subrequest is marked NETFS_SREQ_NEED_RETRY, the retry path in netfs_unbuffered_write() unconditionally calls stream->prepare_write() without checking if it is NULL.

Filesystems such as 9P do not set the prepare_write operation, so stream->prepare_write remains NULL. When get_user_pages() fails with -EFAULT and the subrequest is flagged for retry, this results in a NULL pointer dereference at fs/netfs/direct_write.c:189.

Fix this by mirroring the pattern already used in write_retry.c: if stream->prepare_write is NULL, skip renegotiation and directly reissue the subrequest via netfs_reissue_write(), which handles iterator reset, IN_PROGRESS flag, stats update and reissue internally.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

April 22, 2026

Last Modified

May 19, 2026

Advisory Details (3)

Auto-updated Jun 14, 2026
No patch confirmed yet.
generic

netfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e9075e420a1eb3b52c60f3b95893a55e77419ce8
generic

netfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a4d1b4ba9754bac3efebd06f583a44a7af52c0ab
generic

netfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7a5482f5ce891decbf36f2e6fab1e9fc4a76a684

Vendor Advisories for CVE-2026-31437(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
linuxKernel @ 6.18.21—osv

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(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 40× 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 130 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-31437?
CVE-2026-31437 is a medium vulnerability published on April 22, 2026. In the Linux kernel, the following vulnerability has been resolved: netfs: Fix NULL pointer dereference in netfsunbufferedwrite() on retry When a write subrequest is marked NETFSSREQNEED_RETRY, the retry path in netfsunbufferedwrite() unconditionally calls stream->prepare_write() without checking…
When was CVE-2026-31437 disclosed?
CVE-2026-31437 was first published in the National Vulnerability Database on April 22, 2026, with the most recent update on May 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31437 actively exploited?
CVE-2026-31437 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 97.8% of all scored CVEs.
What is the CVSS score of CVE-2026-31437?
CVE-2026-31437 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-31437?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31437, 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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