CVE-2026-99055

Full vulnerability record from the local CVENow database.

Description

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.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-10-23 13:17:29.140000

Last modified

2026-10-23 13:17:29.140000

View original CVE JSON

{
  "id": "CVE-2026-99055",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-10-23T13:17:29.140",
  "lastModified": "2026-10-23T13:17:29.140",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: reject net_iov in zerocopy receive mapping hints\n\nAfter copying a readable prefix, receive_fallback_to_copy() asks\ntcp_zerocopy_set_hint_for_skb() where page mapping can resume. If the\nnext skb is unreadable, find_next_mappable_frag() passes its net_iov\nfragment to can_map_frag().\n\nskb_frag_page() returns NULL for a net_iov, but can_map_frag()\ndereferences it in PageCompound(). A v7.2 KASAN run on a connected TCP\nsocket with 64 readable bytes followed by a 4096-byte NET_IOV_DMABUF\nfragment reported:\n\n  BUG: KASAN: null-ptr-deref in can_map_frag\n  tcp_zerocopy_receive -> can_map_frag\n  Kernel panic - not syncing: KASAN: panic_on_warn set\n\nThe diagnostic inserted the net_iov directly because the test host has\nno devmem-capable NIC. Hardware end-to-end reachability remains untested\nand requires CONFIG_NET_DEVMEM plus a supported DMA-buf-bound RX queue.\n\nReject all net_iov fragments before skb_frag_page(). This covers both\nDMABUF and IOURING net_iov types while leaving page-backed checks\nunchanged. With the guard, the same queue copied the readable prefix,\nreturned a 4096-byte skip hint, and completed without a fault."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "net/ipv4/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "9f6b619edf2e85746f261b42ae8f818a59d126f7",
              "lessThan": "563d3564513496b9ce3b3ba7a5154427554d0f06",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "9f6b619edf2e85746f261b42ae8f818a59d126f7",
              "lessThan": "1c7463ac0e99cc91c4eecc1b69a740ef1a619932",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "9f6b619edf2e85746f261b42ae8f818a59d126f7",
              "lessThan": "3aa6f536a95eb0617c313ae2eb76fdfa85331f85",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "9f6b619edf2e85746f261b42ae8f818a59d126f7",
              "lessThan": "8b1f0af1fd5fd113432233ed8a3862ee7c30a84f",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "net/ipv4/tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.12",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.12",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.113",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.57",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.11",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1c7463ac0e99cc91c4eecc1b69a740ef1a619932",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3aa6f536a95eb0617c313ae2eb76fdfa85331f85",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/563d3564513496b9ce3b3ba7a5154427554d0f06",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8b1f0af1fd5fd113432233ed8a3862ee7c30a84f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}