{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.176-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.85-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.19.14-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "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-\u003endp_size, the bounds check of: \tndp_index \u003e (block_len - opts-\u003endp_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-\u003edpe_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-\u003endp_size and block_len - opts-\u003edpe_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.",
  "id": "DEBIAN-CVE-2026-31617",
  "modified": "2026-09-14T16:47:50.748708043Z",
  "published": "2026-04-24T15:16:40.973Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-31617"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-31617"
  ]
}