GHSA-J6PG-F87Q-4363

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

net: ethernet: cortina: Carry over frag counter

The gmac_rx() NAPI poll function assembles packets in an SKB from a ring buffer.

If the ring buffer gets completely emptied during a poll cycle, we exit gmac_rx(), but the packet is not yet completely assembled in the SKB, yet the fragment counter frag_nr is reset to zero on the next invocation.

Solve this by making the RX fragment counter a part of the port struct, and carry it over between invocations.

Reset the fragment counter only right after calling napi_gro_frags(), on error (after calling napi_free_frags()) or if stopping the port.

Reset it in some place where not strictly necessary just to emphasize what is going on.

This was found by Sashiko during normal patch review.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-64055"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:45Z",
    "severity": "CRITICAL"
  },
  "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.",
  "id": "GHSA-j6pg-f87q-4363",
  "modified": "2026-07-20T15:31:57Z",
  "published": "2026-07-19T18:31:50Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64055"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/46806096f35b8d3dfa2f321ddd77f597edcdb85f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7123cf481e21b54eb6adc4cb0d8dc2876aeaee41"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/75105fcf73f1ce7d9f769aaefec6e6d6645d5ac0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/78cf08b3be47c28f07008a76c932bad7cdffa9d8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7af1fabdee744b7995fe01b30b77dfc397657cb5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c373b34877afea61c89e0dd2e38948c624249b9b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/df31e3b64455293df1ea89c7da7d5c9bfbcdd253"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ebd8ec2b309e3a447851b456ccaf8fb39f3661e7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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