{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/ip_output.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "83fedc4741210f75be8ca5b487985a242bf6f18d",
              "status": "affected",
              "version": "daba287b299ec7a2c61ae3a714920e90e8396ad5",
              "versionType": "git"
            },
            {
              "lessThan": "81f540827d243b8dad76c1f44e70ea31719f393c",
              "status": "affected",
              "version": "daba287b299ec7a2c61ae3a714920e90e8396ad5",
              "versionType": "git"
            },
            {
              "lessThan": "b83641e0ab8b20eefcc4cdc5a059f897375291a2",
              "status": "affected",
              "version": "daba287b299ec7a2c61ae3a714920e90e8396ad5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/ip_output.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.13"
            },
            {
              "lessThan": "3.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "3.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "3.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "3.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ipv4: Fix UDP length overflow with PMTU discover and big MTU\n\nThis commit bounds cork-\u003ebase.fragsize to IP_MAX_MTU to avoid a\npossible overflow of UDP length that triggers a WARN in\nudp_set_len_short when setsockopt IP_MTU_DISCOVER is set to\nIP_PMTUDISC_PROBE, and a large packet is sent over a netdev with an\nunusually large MTU.\n\nSteps to reproduce:\n\n1. Set device MTU bigger than IP_MAX_MTU + 20. cork-\u003ebase.fragsize will\n   be set to that MTU in ip_setup_cork.\n2. Set IP_MTU_DISCOVER to IP_PMTUDISC_PROBE. It lets maxnonfragsize be\n   set to device MTU (cork-\u003efragsize) in __ip_append_data, rather than\n   to IP_MAX_MTU.\n3. Send 65528 bytes of payload (+8 bytes of UDP header, +20 bytes of\n   IPv4 header). Device MTU allows it (it\u0027s only one byte bigger than\n   IP_MAX_MTU + IPv4 header, and the device MTU is bigger than that).\n4. The UDP length in the built packet is 65536, which overflows the\n   16-bit length field and triggers the WARN in udp_set_len_short.\n\nNote: IP_PMTUDISC_DO with IPv4 is safe, because ip_dst_mtu_maybe_forward\nalways clamps at IP_MAX_MTU, unlike ip6_dst_mtu_maybe_forward.\n\nThe Fixes tag points at the first commit where I could reproduce the\noverflow with IPv4 and IP_PMTUDISC_PROBE."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:18:46.601Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/83fedc4741210f75be8ca5b487985a242bf6f18d"
        },
        {
          "url": "https://git.kernel.org/stable/c/81f540827d243b8dad76c1f44e70ea31719f393c"
        },
        {
          "url": "https://git.kernel.org/stable/c/b83641e0ab8b20eefcc4cdc5a059f897375291a2"
        }
      ],
      "title": "net: ipv4: Fix UDP length overflow with PMTU discover and big MTU",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98393",
    "datePublished": "2026-10-14T13:25:56.697Z",
    "dateReserved": "2026-09-25T10:25:14.346Z",
    "dateUpdated": "2026-10-19T09:18:46.601Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}