inet: frags: strip GSO state from fragments before reassembly

{
  "id": "d42a7c315d05a6db7465e8a19bf34c9f2d50668988a9316bc940a417d7be6200",
  "url": "https://osv.dev/vulnerability/CVE-2026-80590",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "inet: frags: strip GSO state from fragments before reassembly",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: inet: frags: strip GSO state from fragments before reassembly A virtio_net_hdr (tun/tap, or AF_PACKET with PACKET_VNET_HDR) can mark an IPv4 or IPv6 fragment as GSO; nothing relates gso_type to frag_off. inet_frag_reasm_prepare()/inet_frag_reasm_finish() keep the first fragment's skb as the head of the reassembled datagram, including its shinfo->gso_size/gso_type/gso_segs, and chain the remaining fragments on frag_list with whatever linear/paged layout they arrived with. After ip_defrag() (ip_local_deliver(), nf_defrag_ipv4, ...) the reassembled skb therefore still claims to be GSO (SKB_GSO_DODGY), and the next software segmentation point - udp_rcv_segment() on local delivery, validate_xmit_skb(), or the ip_finish_output_gso() slow path - hands it to skb_segment(). skb_segment()'s frag_list walk assumes GRO-shaped input and hits one of its BUG_ON()s. Two writes to a tap by an unprivileged user in its own userns are enough: kernel BUG at net/core/skbuff.c:4899! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 1000 PID: 82 Comm: poc Not tainted 7.2.0-pentest+ #2 RIP: 0010:skb_segment+0x20ca/0x48b0 Call Trace: __udp_gso_segment+0x29a/0x27d0 udp4_ufo_fragment+0x458/0x6c0 inet_gso_segment+0x429/0x1340 skb_mac_gso_segment+0x233/0x4f0 __skb_gso_segment+0x308/0x660 udp_queue_rcv_skb+0x440/0xad0 udp_unicast_rcv_skb+0xc7/0x2c0 udp_rcv+0x16ce/0x2260 ip_protocol_deliver_rcu+0x197/0x2d0 ip_local_deliver+0x430/0",
    "evidence": "osv:CVE-2026-80590",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.268",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.219",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.186",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.155",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.107",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.48",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.12",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-80590",
      "aliases": [
        "CVE-2026-80590"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f43798c27684ab925adde7d8acc34c78c6e50df8"
                },
                {
                  "fixed": "cfdbc8c2e6f9ef5d8b8e54859da03dfe682b0bee"
                },
                {
                  "fixed": "29dda278a5ed272f2230ff4eaa23cf403107bba0"
                },
                {
                  "fixed": "14a8f3e10fa9a5abd6cedcdaa0c0b7ea9a09f234"
                },
                {
                  "fixed": "3edf721bb4b99d272c336631b44e3d8ff9a4f31b"
                },
                {
                  "fixed": "dec2edb7aaf12a8878b3a03172ea8fc277b8eaad"
                },
                {
                  "fixed": "c49f04e8d2b94dbb8d9fd99731dd3f00589c8ace"
                },
                {
                  "fixed": "69b73b74d9eb45f5560a8fe4fa406ada580e1340"
                },
                {
                  "fixed": "da857e448322a2e871ce3ecc2900027041160d43"
                },
                {
                  "fixed": "d5dc1e69fd7258ea605c9952e5d5947539159ae3"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80590.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.27"
                },
                {
                  "fixed": "5.10.268"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.219"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.186"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.155"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.107"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.48"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.12"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.2.0"
                },
                {
                  "fixed": "7.2.2"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80590.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.624381055Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/14a8f3e10fa9a5abd6cedcdaa0c0b7ea9a09f234",
        "https://git.kernel.org/stable/c/29dda278a5ed272f2230ff4eaa23cf403107bba0",
        "https://git.kernel.org/stable/c/3edf721bb4b99d272c336631b44e3d8ff9a4f31b",
        "https://git.kernel.org/stable/c/69b73b74d9eb45f5560a8fe4fa406ada580e1340",
        "https://git.kernel.org/stable/c/c49f04e8d2b94dbb8d9fd99731dd3f00589c8ace",
        "https://git.kernel.org/stable/c/cfdbc8c2e6f9ef5d8b8e54859da03dfe682b0bee",
        "https://git.kernel.org/stable/c/d5dc1e69fd7258ea605c9952e5d5947539159ae3",
        "https://git.kernel.org/stable/c/da857e448322a2e871ce3ecc2900027041160d43",
        "https://git.kernel.org/stable/c/dec2edb7aaf12a8878b3a03172ea8fc277b8eaad",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80590.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-80590",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80590.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-80590",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 499724,
  "published_at": "2026-08-28T06:35:12.516+00:00"
}