tcp: reject net_iov in zerocopy receive mapping hints

{
  "id": "549aef39c253b55b6936e41f5e69102f31599cd69616c68698609aa8cd65c7c1",
  "url": "https://osv.dev/vulnerability/CVE-2026-99055",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tcp: reject net_iov in zerocopy receive mapping hints",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tcp: reject net_iov in zerocopy receive mapping hints After copying a readable prefix, receive_fallback_to_copy() asks tcp_zerocopy_set_hint_for_skb() where page mapping can resume. If the next skb is unreadable, find_next_mappable_frag() passes its net_iov fragment to can_map_frag(). skb_frag_page() returns NULL for a net_iov, but can_map_frag() dereferences it in PageCompound(). A v7.2 KASAN run on a connected TCP socket with 64 readable bytes followed by a 4096-byte NET_IOV_DMABUF fragment reported: BUG: KASAN: null-ptr-deref in can_map_frag tcp_zerocopy_receive -> can_map_frag Kernel panic - not syncing: KASAN: panic_on_warn set The diagnostic inserted the net_iov directly because the test host has no devmem-capable NIC. Hardware end-to-end reachability remains untested and requires CONFIG_NET_DEVMEM plus a supported DMA-buf-bound RX queue. Reject all net_iov fragments before skb_frag_page(). This covers both DMABUF and IOURING net_iov types while leaving page-backed checks unchanged. With the guard, the same queue copied the readable prefix, returned a 4096-byte skip hint, and completed without a fault.",
    "evidence": "osv:CVE-2026-99055",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.113",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.57",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-99055",
      "aliases": [
        "CVE-2026-99055"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "9f6b619edf2e85746f261b42ae8f818a59d126f7"
                },
                {
                  "fixed": "563d3564513496b9ce3b3ba7a5154427554d0f06"
                },
                {
                  "fixed": "1c7463ac0e99cc91c4eecc1b69a740ef1a619932"
                },
                {
                  "fixed": "3aa6f536a95eb0617c313ae2eb76fdfa85331f85"
                },
                {
                  "fixed": "8b1f0af1fd5fd113432233ed8a3862ee7c30a84f"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-99055.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.12.0"
                },
                {
                  "fixed": "6.12.113"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.57"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-99055.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.432559878Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1c7463ac0e99cc91c4eecc1b69a740ef1a619932",
        "https://git.kernel.org/stable/c/3aa6f536a95eb0617c313ae2eb76fdfa85331f85",
        "https://git.kernel.org/stable/c/563d3564513496b9ce3b3ba7a5154427554d0f06",
        "https://git.kernel.org/stable/c/8b1f0af1fd5fd113432233ed8a3862ee7c30a84f",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99055.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-99055",
        "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/2026/99xxx/CVE-2026-99055.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-99055",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 505878,
  "published_at": "2026-10-23T12:22:39.451+00:00"
}