GHSA-7VQV-HXRC-VVX2
Vulnerability from github – Published: 2026-09-24 18:31 – Updated: 2026-09-24 18:31In 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.
{
"affected": [],
"aliases": [
"CVE-2026-93805"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-24T17:17:13Z",
"severity": null
},
"details": "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": "GHSA-7vqv-hxrc-vvx2",
"modified": "2026-09-24T18:31:29Z",
"published": "2026-09-24T18:31:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93805"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0ec738a0d361d7eb37188117166d201f9df622d3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8f4127a93cf60d561ad39849a9ac763ba0e14db5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d5e4586546974179feca305a94e07fac3e9727fe"
}
],
"schema_version": "1.4.0",
"severity": []
}
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