{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64055",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-64055"
  ],
  "published": "2026-07-19T15:41:06Z",
  "summary": "net: ethernet: cortina: Carry over frag counter",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ethernet: cortina: Carry over frag counter\n\nThe gmac_rx() NAPI poll function assembles packets in an\nSKB from a ring buffer.\n\nIf the ring buffer gets completely emptied during a poll cycle,\nwe exit gmac_rx(), but the packet is not yet completely\nassembled in the SKB, yet the fragment counter frag_nr is\nreset to zero on the next invocation.\n\nSolve this by making the RX fragment counter a part of the\nport struct, and carry it over between invocations.\n\nReset the fragment counter only right after calling\nnapi_gro_frags(), on error (after calling napi_free_frags())\nor if stopping the port.\n\nReset it in some place where not strictly necessary just to\nemphasize what is going on.\n\nThis was found by Sashiko during normal patch review.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.175",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64055"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/df31e3b64455293df1ea89c7da7d5c9bfbcdd253"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7af1fabdee744b7995fe01b30b77dfc397657cb5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/75105fcf73f1ce7d9f769aaefec6e6d6645d5ac0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/78cf08b3be47c28f07008a76c932bad7cdffa9d8"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7123cf481e21b54eb6adc4cb0d8dc2876aeaee41"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c373b34877afea61c89e0dd2e38948c624249b9b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/46806096f35b8d3dfa2f321ddd77f597edcdb85f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ebd8ec2b309e3a447851b456ccaf8fb39f3661e7"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 9.8,
      "cvss_v3_severity": "Critical",
      "scenario": "AV:N - The bug is in the Cortina Gemini GMAC RX NAPI path (gmac_rx), which processes incoming Ethernet frames delivered by hardware DMA; a remote attacker on any routable network can send crafted multi-fragment frames to the device's NIC without local access.\nAC:L - An attacker controls frame size (jumbo frames exceeding the 2048-byte RX buffer fragment size) and traffic timing to drain the RX ring mid-packet across NAPI poll cycles, reliably reproducing the lost frag_nr condition without depending on uncontrollable system state.\nPR:N - Exploitation requires only the ability to send Ethernet frames to the target interface; no local account, kernel capability, or authentication on the victim system is needed.\nUI:N - Packet reception and NAPI processing are fully automatic; no victim user action such as mounting a filesystem or opening a file is required.\nS:U - The vulnerability corrupts kernel skb metadata in the network driver and affects only the kernel's own security domain; it does not cross a VM, container, or IOMMU boundary by itself.\nC:H - Resetting frag_nr to zero while rx_skb retains prior fragments causes skb_fill_page_desc to overwrite fragment slot 0, shrinks nr_frags while inflating skb->len, and can trigger out-of-bounds kernel reads when GRO and the network stack process the corrupted skb.\nI:H - The bug corrupts kernel heap skb fragment metadata (overwritten page descriptors, inconsistent nr_frags versus len), which is memory corruption in kernel structures that can be leveraged for arbitrary write or control-flow hijack primitives.\nA:H - Submitting a corrupted multi-fragment skb to napi_gro_frags and the upper network stack can cause kernel oops, BUG, or panic during fragment traversal, checksum, or GRO processing."
    }
  }
}