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wifi: at76c50x-usb: avoid length underflow in at76_guess_freq()

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: wifi: at76c50x-usb: avoid length underflow in at76_guess_freq() at76_guess_freq() checks only that the received frame is at least a bare 802.11 header (24 bytes) before subtracting the fixed management-body offset: len -= el_off; For both beacon and probe response frames, el_off is 36. If the frame is shorter than el_off, subtracting it causes the calculated IE length to wrap. The length is eventually passed to cfg80211_find_elem_match() as a very large unsigned value, so the element walk runs beyond the RX skb. This path is reached from at76_rx_tasklet() while scanning. If the device delivers a truncated beacon or probe response, the oversized IE length causes an out-of-bounds read during scanning. Skip the IE lookup if the frame does not reach the variable elements, before subtracting el_off.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.265, 5.15.216, 6.1.183, 6.12.101, 6.18.42, 6.6.148, 7.1.6
CVEs
CVE-2026-68373
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 04:03 UTC · Revision 1

Source evidence

wifi: at76c50x-usb: avoid length underflow in at76_guess_freq()

core-osv · Original source

Published 10 Aug 2026, 12:03 UTC

In the Linux kernel, the following vulnerability has been resolved: wifi: at76c50x-usb: avoid length underflow in at76_guess_freq() at76_guess_freq() checks only that the received frame is at least a bare 802.11 header (24 bytes) before subtracting the fixed management-body offset: len -= el_off; For both beacon and probe response frames, el_off is 36. If the frame is shorter than el_off, subtracting it causes the calculated IE length to wrap. The length is eventually passed to cfg80211_find_elem_match() as a very large unsigned value, so the element walk runs beyond the RX skb. This path is reached from at76_rx_tasklet() while scanning. If the device delivers a truncated beacon or probe response, the oversized IE length causes an out-of-bounds read during scanning. Skip the IE lookup if the frame does not reach the variable elements, before subtracting el_off.

osv:CVE-2026-68373

Kernel

Fixed versions: 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6

Complete source record
{
  "id": "91ac5b0d4f73218e82c33f4a4eafda204a064ed6050f6abc60b5787753d1a95a",
  "url": "https://osv.dev/vulnerability/CVE-2026-68373",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "wifi: at76c50x-usb: avoid length underflow in at76_guess_freq()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: wifi: at76c50x-usb: avoid length underflow in at76_guess_freq() at76_guess_freq() checks only that the received frame is at least a bare 802.11 header (24 bytes) before subtracting the fixed management-body offset: len -= el_off; For both beacon and probe response frames, el_off is 36. If the frame is shorter than el_off, subtracting it causes the calculated IE length to wrap. The length is eventually passed to cfg80211_find_elem_match() as a very large unsigned value, so the element walk runs beyond the RX skb. This path is reached from at76_rx_tasklet() while scanning. If the device delivers a truncated beacon or probe response, the oversized IE length causes an out-of-bounds read during scanning. Skip the IE lookup if the frame does not reach the variable elements, before subtracting el_off.",
    "evidence": "osv:CVE-2026-68373",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.265",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.216",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.183",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.148",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.101",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.42",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-68373",
      "aliases": [
        "CVE-2026-68373"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"
        }
      ],
      "affected": [
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              "events": [
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                {
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                {
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          "database_specific": {
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          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.30"
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                {
                  "fixed": "5.10.265"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.216"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
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                  "fixed": "6.1.183"
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              ]
            },
            {
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                  "introduced": "6.2.0"
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            },
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                  "introduced": "6.7.0"
                },
                {
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            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.42"
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            {
              "type": "ECOSYSTEM",
              "events": [
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
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        }
      ],
      "modified": "2026-10-28T02:30:33.033380575Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/4875680d1703f56afa6257ba30244f2fb44ed205",
        "https://git.kernel.org/stable/c/61a799ffd1e5a4fd3702d547828b7ff3d161468e",
        "https://git.kernel.org/stable/c/b406f33d234f98c8b310fdab5cbb492d85e98e49",
        "https://git.kernel.org/stable/c/bcde7249d45f52f994a9872bedf45994472ade77",
        "https://git.kernel.org/stable/c/cb831aff2f850f72bc5ff5ad77d0a70bb5a84061",
        "https://git.kernel.org/stable/c/e165a1d295e7e814e13b0f92c86e5d48309509ce",
        "https://git.kernel.org/stable/c/f742d9c98b5c504fc9e6744eef13a721c2aea486",
        "https://git.kernel.org/stable/c/fb1b50ab699211e777dca5ccfb648788b6a6e519",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68373.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-68373",
        "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/2026/68xxx/CVE-2026-68373.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-68373",
        "evidence": "/id"
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    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 500210,
  "published_at": "2026-08-10T12:03:51.663+00:00"
}