FKIE_CVE-2026-93805

Vulnerability from fkie_nvd - Published: 2026-09-24 17:17 - Updated: 2026-09-25 13:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: cfg80211: validate rx/tx MLME callback frame lengths before access cfg80211_rx_mlme_mgmt() and cfg80211_tx_mlme_mgmt() call tracepoints before rejecting frames shorter than the frame-control field. After that, they only require len >= 2 before dispatching into subtype handlers that assume their fixed fields are present. The frames that trip this are not shorter than 2 bytes; they are short relative to their subtype. mwifiex is a concrete in-tree example on the length side: mwifiex_process_mgmt_packet() only requires a 4-address ieee80211_hdr plus the 2-byte firmware length prefix before handing the frame to cfg80211_rx_mlme_mgmt(). After stripping the length prefix and removing addr4, pkt_len can be exactly 24: a bare 3-address management header with no reason-code body. The existing WARN_ON(len < 2) does not fire on such a frame, and cfg80211_process_deauth() then reads u.deauth.reason_code as a two-byte access starting at offset 24, immediately past the 24-byte buffer. Add a frame-control length gate, then validate each subtype's minimum frame size in an if/else-if chain that mirrors the dispatch logic. Trace only after the frame is known to be well-formed. Side effects of this change: - The WARN_ON(len < 2) is dropped. It only guarded the frame_control read, never the subtype fixed fields, and it does not fire on the frames that actually trigger the out-of-bounds read (which are >= 2). The len >= 2 check is kept as the guard before dereferencing frame_control, but without the warning: these are exported callbacks and a malformed frame from a driver should be dropped silently rather than backtraced. - cfg80211_tx_mlme_mgmt() previously routed every non-deauth subtype through disassociation handling; it now silently ignores unrecognised subtypes.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0ec738a0d361d7eb37188117166d201f9df622d3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8f4127a93cf60d561ad39849a9ac763ba0e14db5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d5e4586546974179feca305a94e07fac3e9727fe
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/wireless/mlme.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0ec738a0d361d7eb37188117166d201f9df622d3",
              "status": "affected",
              "version": "6829c878ecd24ff0ae41b4668c7e9d0f11b66942",
              "versionType": "git"
            },
            {
              "lessThan": "8f4127a93cf60d561ad39849a9ac763ba0e14db5",
              "status": "affected",
              "version": "6829c878ecd24ff0ae41b4668c7e9d0f11b66942",
              "versionType": "git"
            },
            {
              "lessThan": "d5e4586546974179feca305a94e07fac3e9727fe",
              "status": "affected",
              "version": "6829c878ecd24ff0ae41b4668c7e9d0f11b66942",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/wireless/mlme.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.32"
            },
            {
              "lessThan": "2.6.32",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: cfg80211: validate rx/tx MLME callback frame lengths before access\n\ncfg80211_rx_mlme_mgmt() and cfg80211_tx_mlme_mgmt() call tracepoints\nbefore rejecting frames shorter than the frame-control field. After\nthat, they only require len \u003e= 2 before dispatching into subtype\nhandlers that assume their fixed fields are present.\n\nThe frames that trip this are not shorter than 2 bytes; they are short\nrelative to their subtype. mwifiex is a concrete in-tree example on the\nlength side: mwifiex_process_mgmt_packet() only requires a 4-address\nieee80211_hdr plus the 2-byte firmware length prefix before handing the\nframe to cfg80211_rx_mlme_mgmt(). After stripping the length prefix and\nremoving addr4, pkt_len can be exactly 24: a bare 3-address management\nheader with no reason-code body. The existing WARN_ON(len \u003c 2) does not\nfire on such a frame, and cfg80211_process_deauth() then reads\nu.deauth.reason_code as a two-byte access starting at offset 24,\nimmediately past the 24-byte buffer.\n\nAdd a frame-control length gate, then validate each subtype\u0027s minimum\nframe size in an if/else-if chain that mirrors the dispatch logic. Trace\nonly after the frame is known to be well-formed.\n\nSide effects of this change:\n - The WARN_ON(len \u003c 2) is dropped. It only guarded the frame_control\n   read, never the subtype fixed fields, and it does not fire on the\n   frames that actually trigger the out-of-bounds read (which are \u003e= 2).\n   The len \u003e= 2 check is kept as the guard before dereferencing\n   frame_control, but without the warning: these are exported callbacks\n   and a malformed frame from a driver should be dropped silently rather\n   than backtraced.\n - cfg80211_tx_mlme_mgmt() previously routed every non-deauth subtype\n   through disassociation handling; it now silently ignores unrecognised\n   subtypes."
    }
  ],
  "id": "CVE-2026-93805",
  "lastModified": "2026-09-25T13:17:21.353",
  "metrics": {},
  "published": "2026-09-24T17:17:13.460",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0ec738a0d361d7eb37188117166d201f9df622d3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8f4127a93cf60d561ad39849a9ac763ba0e14db5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d5e4586546974179feca305a94e07fac3e9727fe"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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