CVE-2026-31617

MEDIUM EPSS 2.6%
Published Apr 24, 20262mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Apr 24, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

Description

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 Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
2.6% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 5

VendorProductVersionRange
linuxlinux_kernel*≥5.9  –  <6.6.136
linuxlinux_kernel*≥6.12  –  <6.12.83
linuxlinux_kernel*≥6.13  –  <6.18.24
linuxlinux_kernel*≥6.19  –  <6.19.14
linuxlinux_kernel*≥7.0  –  <7.0.1

References 9

  • git.kernel.org https://git.kernel.org/stable/c/068a7f2749fff6462a0a908ec415b885fe430f50
  • git.kernel.org https://git.kernel.org/stable/c/0f156bb5334e588034ca68ac2ee92b23f66e56e7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/1425655c2870054c3ab4712e2b6dbdd331597ada
  • git.kernel.org https://git.kernel.org/stable/c/6762f8a95772265dd0c2ffe7f400493f3115b135
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/74908b0318d1df1188457040b8714ff4d4b68126
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8757a2593631443648218244b9788e193ae0fdc1
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8b3b7bd3c02f98634baaf36c7fc7ac915f6517ca
  • git.kernel.org https://git.kernel.org/stable/c/8f993d30b95dc9557a8a96ceca11abed674c8acb
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/d58ba8f6546232f8414f396c189297dbee03f1a7
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/0f156bb5334e588034ca68ac2ee92b23f66e56e7
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/6762f8a95772265dd0c2ffe7f400493f3115b135
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/74908b0318d1df1188457040b8714ff4d4b68126
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8757a2593631443648218244b9788e193ae0fdc1
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8f993d30b95dc9557a8a96ceca11abed674c8acb
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/d58ba8f6546232f8414f396c189297dbee03f1a7
    Patch