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net: lan743x: fix RX checksum use-after-free

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net: lan743x: fix RX checksum use-after-free lan743x_rx_process_buffer() adds each non-first receive buffer to the head skb's frag_list. On the last descriptor, lan743x_rx_trim_skb() linearizes the head and frees the fragment skb metadata. The checksum-success path then writes ip_summed through the local skb pointer, which still points to the final fragment. This causes a use-after-free write when a packet spans more than one receive buffer. Set ip_summed on the surviving head skb instead. Multi-buffer receive can occur after a live MTU increase because existing ring entries keep their old buffer size until they are replenished. A KUnit test invoking lan743x_rx_process_buffer() with a two-buffer packet produced a one-byte KASAN use-after-free write before this change. The same test passed after the change. The driver object also builds with W=1. This was not tested on physical LAN743x hardware.

Announced Source revision 1
Original source ↗

CVE-2026-98239

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98239

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a",
        "lessThan": "0e52886c4324c9897c2c62f92be3dc8316cee67e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a",
        "lessThan": "a58024835c704419bb46d2a34e5223f65605f958",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a",
        "lessThan": "6fe5c3a2503983abb431d93faeadfc7f5e6a7e33",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a",
        "lessThan": "5c216bfa9fb7b36804485e67975e9c98055b31ef",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a",
        "lessThan": "161a403c8625e152de03d1da22bbf9cda6dc9f9f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a",
        "lessThan": "a9ce4053dc945c5372dedba5017ee675b30dc0c5",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/net/ethernet/microchip/lan743x_main.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.1"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.1",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.189",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.112",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.54",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.8",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/net/ethernet/microchip/lan743x_main.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98239

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#38319 · Revision 1
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Publisher date
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