CVE-2026-31617

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-04-24. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 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:

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb()

The block_len read from the host-supplied NTB header is checked against ntb_max but has no lower bound. When block_len is smaller than opts->ndp_size, the bounds check of: ndp_index > (block_len - opts->ndp_size) will underflow producing a huge unsigned value that ndp_index can never exceed, defeating the check entirely.

The same underflow occurs in the datagram index checks against block_len

  • opts->dpe_size. With those checks neutered, a malicious USB host can
choose ndp_index and datagram offsets that point past the actual transfer, and the skb_put_data() copies adjacent kernel memory into the network skb.

Fix this by rejecting block lengths that cannot hold at least the NTB header plus one NDP. This will make block_len - opts->ndp_size and block_len - opts->dpe_size both well-defined.

Commit 8d2b1a1ec9f5 ("CDC-NCM: avoid overflow in sanity checking") fixed a related class of issues on the host side of NCM.

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
2.9%
KEV
Not listed

Published

April 24, 2026

Last Modified

July 15, 2026

Advisory Details (10)

Auto-updated Jul 19, 2026
Patch available. Sources: redhat.
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-31617
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d58ba8f6546232f8414f396c189297dbee03f1a7
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8f993d30b95dc9557a8a96ceca11abed674c8acb
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8b3b7bd3c02f98634baaf36c7fc7ac915f6517ca
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8757a2593631443648218244b9788e193ae0fdc1
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/74908b0318d1df1188457040b8714ff4d4b68126
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6762f8a95772265dd0c2ffe7f400493f3115b135
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1425655c2870054c3ab4712e2b6dbdd331597ada
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0f156bb5334e588034ca68ac2ee92b23f66e56e7
generic

usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/068a7f2749fff6462a0a908ec415b885fe430f50

Vendor Advisories for CVE-2026-31617(2)

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 @ 5.10.258—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 15× in last 7d / 49× 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 126 total refreshes for this CVE.

  1. 2026-07-23 14:18 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:08 UTCEG score recompute
  4. 2026-07-22 14:08 UTCEPSS rescore
  5. 2026-07-22 14:08 UTCEPSS rescore
  6. 2026-07-21 15:24 UTCEPSS rescore
  7. 2026-07-21 15:24 UTCEPSS rescore
  8. 2026-07-20 17:08 UTCEPSS rescore
  9. 2026-07-20 17:08 UTCEPSS rescore
  10. 2026-07-19 23:08 UTCOSV refresh
  11. 2026-07-19 14:31 UTCEPSS rescore
  12. 2026-07-19 14:31 UTCEPSS rescore
  13. 2026-07-19 02:29 UTCEPSS rescore
  14. 2026-07-18 10:04 UTCEPSS rescore
  15. 2026-07-18 10:04 UTCEPSS rescore
  16. 2026-07-16 17:03 UTCEPSS rescore
  17. 2026-07-16 17:03 UTCEPSS rescore
  18. 2026-07-15 16:57 UTCEPSS rescore
  19. 2026-07-15 16:57 UTCEPSS rescore
  20. 2026-07-15 02:23 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  21. 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v3 → 7 · severity → HIGH
  22. 2026-07-13 22:30 UTCEPSS rescore
  23. 2026-07-13 06:13 UTCEPSS rescore
  24. 2026-07-13 06:13 UTCEPSS rescore
  25. 2026-07-12 05:46 UTCEPSS rescore
Show 75 more
  1. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 15:15 UTCEPSS rescore
  4. 2026-07-07 13:46 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 16:27 UTCEPSS rescore
  7. 2026-07-06 02:23 UTCEPSS rescore
  8. 2026-07-06 02:23 UTCEPSS rescore
  9. 2026-07-04 06:31 UTCEPSS rescore
  10. 2026-07-01 15:06 UTCEPSS rescore
  11. 2026-06-30 23:22 UTCEPSS rescore
  12. 2026-06-30 04:32 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  13. 2026-06-29 14:06 UTCEPSS rescore
  14. 2026-06-29 14:06 UTCEPSS rescore
  15. 2026-06-28 14:07 UTCEPSS rescore
  16. 2026-06-28 14:07 UTCEPSS rescore
  17. 2026-06-28 04:56 UTCEPSS rescore
  18. 2026-06-28 04:56 UTCEPSS rescore
  19. 2026-06-27 03:08 UTCEPSS rescore
  20. 2026-06-25 13:49 UTCEPSS rescore
  21. 2026-06-25 13:49 UTCEPSS rescore
  22. 2026-06-24 14:05 UTCEPSS rescore
  23. 2026-06-23 21:33 UTCEPSS rescore
  24. 2026-06-23 21:33 UTCEPSS rescore
  25. 2026-06-22 14:25 UTCEPSS rescore
  26. 2026-06-22 14:25 UTCEPSS rescore
  27. 2026-06-21 14:56 UTCEPSS rescore
  28. 2026-06-21 14:56 UTCEPSS rescore
  29. 2026-06-21 01:59 UTCEPSS rescore
  30. 2026-06-19 19:25 UTCEPSS rescore
  31. 2026-06-19 19:25 UTCEPSS rescore
  32. 2026-06-17 17:53 UTCEPSS rescore
  33. 2026-06-16 17:52 UTCEPSS rescore
  34. 2026-06-15 17:49 UTCEPSS rescore
  35. 2026-06-14 23:28 UTCMITRE cvelistV5
  36. 2026-06-14 23:18 UTCEPSS rescore
  37. 2026-06-14 11:52 UTCGHSA enrichment
  38. 2026-06-13 23:00 UTCEPSS rescore
  39. 2026-06-12 23:12 UTCEPSS rescore
  40. 2026-06-12 23:12 UTCEPSS rescore
  41. 2026-06-12 12:27 UTCGHSA enrichment
  42. 2026-06-11 14:01 UTCGHSA enrichment
  43. 2026-06-11 14:00 UTCEPSS rescore
  44. 2026-06-10 22:18 UTCEPSS rescore
  45. 2026-06-10 13:22 UTCEPSS rescore
  46. 2026-06-10 02:58 UTCGHSA enrichment
  47. 2026-06-09 04:32 UTCGHSA enrichment
  48. 2026-06-08 14:17 UTCEPSS rescore
  49. 2026-06-08 14:17 UTCEPSS rescore
  50. 2026-06-08 06:05 UTCGHSA enrichment
  51. 2026-06-07 15:25 UTCEPSS rescore
  52. 2026-06-07 15:25 UTCEPSS rescore
  53. 2026-06-07 15:25 UTCEPSS rescore
  54. 2026-06-07 07:39 UTCGHSA enrichment
  55. 2026-06-06 13:47 UTCEPSS rescore
  56. 2026-06-06 13:47 UTCEPSS rescore
  57. 2026-06-06 09:13 UTCGHSA enrichment
  58. 2026-06-05 22:47 UTCEPSS rescore
  59. 2026-06-05 22:47 UTCEPSS rescore
  60. 2026-06-05 10:46 UTCGHSA enrichment
  61. 2026-06-05 06:10 UTCEPSS rescore
  62. 2026-06-05 06:10 UTCEPSS rescore
  63. 2026-06-04 13:12 UTCEPSS rescore
  64. 2026-06-04 13:12 UTCEPSS rescore
  65. 2026-06-04 11:06 UTCGHSA enrichment
  66. 2026-06-03 11:28 UTCGHSA enrichment
  67. 2026-06-02 20:13 UTCEPSS rescore
  68. 2026-06-02 20:13 UTCEPSS rescore
  69. 2026-06-02 12:03 UTCGHSA enrichment
  70. 2026-06-01 13:51 UTCEPSS rescore
  71. 2026-06-01 13:51 UTCEPSS rescore
  72. 2026-06-01 13:23 UTCGHSA enrichment
  73. 2026-05-31 22:30 UTCEPSS rescore
  74. 2026-05-31 22:30 UTCEPSS rescore
  75. 2026-05-31 00:16 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-31617?
CVE-2026-31617 is a medium vulnerability published on April 24, 2026. In the Linux kernel, the following vulnerability has been resolved: usb: gadget: fncm: validate minimum blocklen in ncmunwrapntb() The block_len read from the host-supplied NTB header is checked against ntbmax but has no lower bound. When blocklen is smaller than opts->ndp_size, the bounds check…
When was CVE-2026-31617 disclosed?
CVE-2026-31617 was first published in the National Vulnerability Database on April 24, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31617 actively exploited?
CVE-2026-31617 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-31617?
CVE-2026-31617 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-31617?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31617, 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.

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