CVE-2026-31478

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-04-22. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: 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:

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()

After this commit (e2b76ab8b5c9 "ksmbd: add support for read compound"), response buffer management was changed to use dynamic iov array. In the new design, smb2_calc_max_out_buf_len() expects the second argument (hdr2_len) to be the offset of ->Buffer field in the response structure, not a hardcoded magic number. Fix the remaining call sites to use the correct offsetof() value.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity98% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
41%
KEV
Not listed

Published

April 22, 2026

Last Modified

August 5, 2026

Advisory Details (7)

Auto-updated Sep 9, 2026
No patch confirmed yet.
generic

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0e55f63dd08f09651d39e1b709a91705a8a0ddcb
generic

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/4cb537ae4f37d7d0f617815ed4bed7173fb50861
generic

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/80824c7e527b70cf9039534e60aff592e8f209d1
generic

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6aef1765d6807e0f027cd87f6ac973eb0879a46d
generic

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683
generic

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9a7166f0ef8cbb7bb48dd05e2471d995566003f5
generic

ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/70b4c414889492c522b6e4331562360f49be2361

Vendor Advisories for CVE-2026-31478(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 @ 5.15.203—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.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux-6.16.1.106-3~deb11u1 ... 6.1.164-1~deb11u1 (16 versions)6.1.170-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (48 versions)6.1.170-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)6.12.85-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (124 versions)6.19.11-1—

Additional Vendor Advisories

(24)

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 5× 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 398 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-31478?
CVE-2026-31478 is a critical vulnerability published on April 22, 2026. In the Linux kernel, the following vulnerability has been resolved: ksmbd: replace hardcoded hdr2len with offsetof() in smb2calcmaxoutbuflen() After this commit (e2b76ab8b5c9 "ksmbd: add support for read compound"), response buffer management was changed to use dynamic iov array. In the new design,…
When was CVE-2026-31478 disclosed?
CVE-2026-31478 was first published in the National Vulnerability Database on April 22, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31478 actively exploited?
CVE-2026-31478 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 58.5% of all scored CVEs.
What is the CVSS score of CVE-2026-31478?
CVE-2026-31478 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-31478?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31478, 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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