CVE-2026-31617 (GCVE-0-2026-31617)
Vulnerability from cvelistv5
Published
2026-04-24 14:42
Modified
2026-04-27 13:56
Severity ?
Summary
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: 2b74b0a04d3e9f9f08ff026e5663dce88ff94e52
Version: 2b74b0a04d3e9f9f08ff026e5663dce88ff94e52
Version: 2b74b0a04d3e9f9f08ff026e5663dce88ff94e52
Version: 2b74b0a04d3e9f9f08ff026e5663dce88ff94e52
Version: 2b74b0a04d3e9f9f08ff026e5663dce88ff94e52
Version: 2b74b0a04d3e9f9f08ff026e5663dce88ff94e52
Version: f7e0611e207d8908c4f2858e244370529a76dbf7
Version: b88ad6e714284b33a47834f5f2a294c2b37c66aa
Version: 471b23586387a32857778c511be60ab31c98dcfd
Version: 4f529c4d1e436230d3af7c09a3239677a14d2b46
Version: ae6a5394d9fbe118bc95cfe376d6a9d91d7547e8
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_ncm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0f156bb5334e588034ca68ac2ee92b23f66e56e7",
              "status": "affected",
              "version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
              "versionType": "git"
            },
            {
              "lessThan": "8757a2593631443648218244b9788e193ae0fdc1",
              "status": "affected",
              "version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
              "versionType": "git"
            },
            {
              "lessThan": "6762f8a95772265dd0c2ffe7f400493f3115b135",
              "status": "affected",
              "version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
              "versionType": "git"
            },
            {
              "lessThan": "d58ba8f6546232f8414f396c189297dbee03f1a7",
              "status": "affected",
              "version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
              "versionType": "git"
            },
            {
              "lessThan": "74908b0318d1df1188457040b8714ff4d4b68126",
              "status": "affected",
              "version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
              "versionType": "git"
            },
            {
              "lessThan": "8f993d30b95dc9557a8a96ceca11abed674c8acb",
              "status": "affected",
              "version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f7e0611e207d8908c4f2858e244370529a76dbf7",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b88ad6e714284b33a47834f5f2a294c2b37c66aa",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "471b23586387a32857778c511be60ab31c98dcfd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4f529c4d1e436230d3af7c09a3239677a14d2b46",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ae6a5394d9fbe118bc95cfe376d6a9d91d7547e8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/function/f_ncm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.9"
            },
            {
              "lessThan": "5.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.136",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.83",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.24",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.136",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.83",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.24",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.14",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.1",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1-rc1",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.9.235",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.14.196",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.19.143",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.4.62",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.8.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb()\n\nThe block_len read from the host-supplied NTB header is checked against\nntb_max but has no lower bound. When block_len is smaller than\nopts-\u003endp_size, the bounds check of:\n\tndp_index \u003e (block_len - opts-\u003endp_size)\nwill underflow producing a huge unsigned value that ndp_index can never\nexceed, defeating the check entirely.\n\nThe same underflow occurs in the datagram index checks against block_len\n- opts-\u003edpe_size.  With those checks neutered, a malicious USB host can\nchoose ndp_index and datagram offsets that point past the actual\ntransfer, and the skb_put_data() copies adjacent kernel memory into the\nnetwork skb.\n\nFix this by rejecting block lengths that cannot hold at least the NTB\nheader plus one NDP.  This will make block_len - opts-\u003endp_size and\nblock_len - opts-\u003edpe_size both well-defined.\n\nCommit 8d2b1a1ec9f5 (\"CDC-NCM: avoid overflow in sanity checking\") fixed\na related class of issues on the host side of NCM."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-27T13:56:57.661Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0f156bb5334e588034ca68ac2ee92b23f66e56e7"
        },
        {
          "url": "https://git.kernel.org/stable/c/8757a2593631443648218244b9788e193ae0fdc1"
        },
        {
          "url": "https://git.kernel.org/stable/c/6762f8a95772265dd0c2ffe7f400493f3115b135"
        },
        {
          "url": "https://git.kernel.org/stable/c/d58ba8f6546232f8414f396c189297dbee03f1a7"
        },
        {
          "url": "https://git.kernel.org/stable/c/74908b0318d1df1188457040b8714ff4d4b68126"
        },
        {
          "url": "https://git.kernel.org/stable/c/8f993d30b95dc9557a8a96ceca11abed674c8acb"
        }
      ],
      "title": "usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31617",
    "datePublished": "2026-04-24T14:42:36.191Z",
    "dateReserved": "2026-03-09T15:48:24.123Z",
    "dateUpdated": "2026-04-27T13:56:57.661Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.