{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"
            },
            {
              "fixed": "a716a64a4ba68cd46f2745fba2b1099fe8e0aa59"
            },
            {
              "fixed": "515b6816ba0c12d8415c88e5f41e6ec029e35cfa"
            },
            {
              "fixed": "74ce7389f8f562d39015f59a00ef7ad6acd37803"
            },
            {
              "fixed": "b0ea911453ce7210e8200a07a94d2458bd1e6430"
            },
            {
              "fixed": "36e0741833bd823866f8cb9f112f37cea1a70b60"
            },
            {
              "fixed": "d9d1a676b033acabf8e5645f730486d1f8204a3f"
            },
            {
              "fixed": "3556beb8ca86677af2aca5bfbed6f8e790fccc83"
            },
            {
              "fixed": "c8a74adccaf028223054633b532593101dfcc581"
            },
            {
              "fixed": "c0726f0caf8c6b3208552949e17d23634a2f3129"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.12"
            },
            {
              "fixed": "5.10.267"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.218"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.185"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.154"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.106"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.47"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.11"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "7.2.0"
            },
            {
              "fixed": "7.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80793.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: reject undersized MTUs in ip_do_fragment()\n\nip_do_fragment() subtracts the IPv4 header length from the effective\nMTU and passes the resulting payload MTU to ip_frag_next().\n\nIf the effective MTU is smaller than hlen + 8, ip_frag_next() rounds\nthe fragment payload length down to zero. The fragmentation state then\nnever makes forward progress: state-\u003eleft, state-\u003eptr and state-\u003eoffset\nstay unchanged while ip_do_fragment() keeps allocating and transmitting\nheader-only fragments until the softlockup detector fires.\n\nThis is reproducible with a route installed using \"mtu lock 20\", but it\nis also reproducible without route MTU lock, for example by forwarding a\npacket to a device whose MTU is 20.\n\nFix it in ip_do_fragment() by rejecting mtu \u003c hlen + 8 with -EMSGSIZE,\nmatching the existing IPv6 fragmentation check.",
  "id": "CVE-2026-80793",
  "modified": "2026-09-06T03:30:56.222197129Z",
  "published": "2026-09-04T15:13:05.814Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3556beb8ca86677af2aca5bfbed6f8e790fccc83"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/36e0741833bd823866f8cb9f112f37cea1a70b60"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/515b6816ba0c12d8415c88e5f41e6ec029e35cfa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/74ce7389f8f562d39015f59a00ef7ad6acd37803"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a716a64a4ba68cd46f2745fba2b1099fe8e0aa59"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b0ea911453ce7210e8200a07a94d2458bd1e6430"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c0726f0caf8c6b3208552949e17d23634a2f3129"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c8a74adccaf028223054633b532593101dfcc581"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d9d1a676b033acabf8e5645f730486d1f8204a3f"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80793.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80793"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ipv4: reject undersized MTUs in ip_do_fragment()"
}