{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "7266507d89991fa1e989283e4e032c6d9357fe26"
            },
            {
              "fixed": "bded21a4bf9bf86a79148be735723a97ca9a7532"
            },
            {
              "fixed": "dc11f26685aa850f237226f0f463647aea58ab7c"
            },
            {
              "fixed": "e38143c9b477f2968024c47c647dd4456a40aff1"
            },
            {
              "fixed": "57e4e29644ec054d7021d296407e7ddd844afea2"
            },
            {
              "fixed": "eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17"
            },
            {
              "fixed": "2bcf2c5052fb5e73e255140ab43f056aef409c27"
            },
            {
              "fixed": "0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7"
            },
            {
              "fixed": "77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.9.0"
            },
            {
              "fixed": "5.10.261"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.212"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72251.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_nat_sip: reload possible stale data pointer\n\nquoting sashiko:\n ------------------------------------------------------------------------\n [..] noticed a potential memory bug and header corruption involving the\n SIP NAT helper.\n\n In net/netfilter/nf_nat_sip.c:nf_nat_sip():\n\tif (skb_ensure_writable(skb, skb-\u003elen)) {\n\t\tnf_ct_helper_log(skb, ct, \"cannot mangle packet\");\n\t\treturn NF_DROP;\n\t}\n\tuh = (void *)skb-\u003edata + protoff;\n\tuh-\u003edest = ct_sip_info-\u003eforced_dport;\n\tif (!nf_nat_mangle_udp_packet(skb, ct, ctinfo, protoff,\n\t\t\t\t      0, 0, NULL, 0)) {\n\n If a cloned or fragmented SKB is reallocated by skb_ensure_writable(), the\n old data buffer is freed. However, nf_nat_sip() fails to update *dptr to\n point to the new buffer.\n\n It also appears to use nf_nat_mangle_udp_packet() on what could be a TCP\n packet, which would overwrite the sequence number with a checksum update.\n ------------------------------------------------------------------------\n\nnf_conntrack_sip linerizes skbs, hence no fragmented skb can be seen.\nBut clones are possible, so rebuild dptr.\n\nDisable nf_nat_mangle_udp_packet() branch for TCP streams.\nIt doesn't look like this can ever happen, else we should have received\nbug reports about this, so just check the conntrack is UDP and drop\notherwise.\n\nThe calling conntrack_sip set -\u003eforced_dport for SIP_HDR_VIA_UDP messages,\nso I don't think this is ever expected to be true for a TCP stream.",
  "id": "CVE-2026-72251",
  "modified": "2026-08-18T03:31:04.198398824Z",
  "published": "2026-08-15T05:54:39.983Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0e76e3e886cc9ee027337d5ad39cb96f57b7bdc7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2bcf2c5052fb5e73e255140ab43f056aef409c27"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/57e4e29644ec054d7021d296407e7ddd844afea2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/77e43bcb7ec177e293a5c3f1b91a2c5aebfb6c68"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bded21a4bf9bf86a79148be735723a97ca9a7532"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dc11f26685aa850f237226f0f463647aea58ab7c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e38143c9b477f2968024c47c647dd4456a40aff1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eae9c6ccb5af69c713a65f8ae219f5c1aa32cd17"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72251.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72251"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "netfilter: nf_nat_sip: reload possible stale data pointer"
}