GHSA-C488-CCG3-WFCM

Vulnerability from github – Published: 2026-08-15 15:30 – Updated: 2026-08-19 18:32
VLAI
Details

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

wifi: mwifiex: use the subframe length when parsing A-MSDU TDLS frames

mwifiex_11n_dispatch_amsdu_pkt() splits an A-MSDU with ieee80211_amsdu_to_8023s() and walks the resulting subframes. For each subframe it passes the subframe data pointer to mwifiex_process_tdls_action_frame(), but pairs it with skb->len, the length of the A-MSDU parent, instead of rx_skb->len:

rx_skb = __skb_dequeue(&list);
rx_hdr = (struct rx_packet_hdr *)rx_skb->data;
if (ISSUPP_TDLS_ENABLED(priv->adapter->fw_cap_info) &&
    ntohs(rx_hdr->eth803_hdr.h_proto) == ETH_P_TDLS) {
    mwifiex_process_tdls_action_frame(priv, (u8 *)rx_hdr,
                      skb->len);
}

The parent is not a valid description of that buffer, and may not be valid memory at all. ieee80211_amsdu_to_8023s() ends with

if (!reuse_skb)
    dev_kfree_skb(skb);

and it only sets reuse_skb when the parent is linear, is not a head_frag, and is being consumed as the last subframe. So when the parent does not qualify for reuse it has already been freed, and the read of skb->len is a use-after-free. When it is reused, skb->len is the length of the last subframe, applied to every earlier subframe, which over-states the buffer whenever an earlier subframe is shorter.

The callee cannot absorb a wrong length, because it derives its own ceiling from the value it is given. Each frame type computes

ies_len = len - sizeof(struct ethhdr) - TDLS_*_FIX_LEN;

and the element walk is then bounded entirely against that ceiling,

for (end = pos + ies_len; pos + 1 < end; pos += 2 + pos[1]) {
    u8 ie_len = pos[1];

    if (pos + 2 + ie_len > end)
        break;

so a too-large len moves end past the end of the subframe and the walk reads and copies beyond it. The A-MSDU layout is chosen by the sender, which makes the difference between the last subframe and a shorter earlier one remotely selectable. Reaching this requires TDLS support in firmware and the TDLS ethertype on the subframe.

The other caller, mwifiex_process_rx_packet(), is correct: it passes a pointer and a length that describe the same region of the RX buffer.

Pass rx_skb->len, the length of the subframe actually being parsed.

Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-74488"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T13:17:53Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mwifiex: use the subframe length when parsing A-MSDU TDLS frames\n\nmwifiex_11n_dispatch_amsdu_pkt() splits an A-MSDU with\nieee80211_amsdu_to_8023s() and walks the resulting subframes. For each\nsubframe it passes the subframe data pointer to\nmwifiex_process_tdls_action_frame(), but pairs it with skb-\u003elen, the\nlength of the A-MSDU parent, instead of rx_skb-\u003elen:\n\n\trx_skb = __skb_dequeue(\u0026list);\n\trx_hdr = (struct rx_packet_hdr *)rx_skb-\u003edata;\n\tif (ISSUPP_TDLS_ENABLED(priv-\u003eadapter-\u003efw_cap_info) \u0026\u0026\n\t    ntohs(rx_hdr-\u003eeth803_hdr.h_proto) == ETH_P_TDLS) {\n\t\tmwifiex_process_tdls_action_frame(priv, (u8 *)rx_hdr,\n\t\t\t\t\t\t  skb-\u003elen);\n\t}\n\nThe parent is not a valid description of that buffer, and may not be\nvalid memory at all. ieee80211_amsdu_to_8023s() ends with\n\n\tif (!reuse_skb)\n\t\tdev_kfree_skb(skb);\n\nand it only sets reuse_skb when the parent is linear, is not a\nhead_frag, and is being consumed as the *last* subframe. So when the\nparent does not qualify for reuse it has already been freed, and the\nread of skb-\u003elen is a use-after-free. When it is reused, skb-\u003elen is\nthe length of the last subframe, applied to every earlier subframe,\nwhich over-states the buffer whenever an earlier subframe is shorter.\n\nThe callee cannot absorb a wrong length, because it derives its own\nceiling from the value it is given. Each frame type computes\n\n\ties_len = len - sizeof(struct ethhdr) - TDLS_*_FIX_LEN;\n\nand the element walk is then bounded entirely against that ceiling,\n\n\tfor (end = pos + ies_len; pos + 1 \u003c end; pos += 2 + pos[1]) {\n\t\tu8 ie_len = pos[1];\n\n\t\tif (pos + 2 + ie_len \u003e end)\n\t\t\tbreak;\n\nso a too-large len moves end past the end of the subframe and the walk\nreads and copies beyond it. The A-MSDU layout is chosen by the sender,\nwhich makes the difference between the last subframe and a shorter\nearlier one remotely selectable. Reaching this requires TDLS support in\nfirmware and the TDLS ethertype on the subframe.\n\nThe other caller, mwifiex_process_rx_packet(), is correct: it passes a\npointer and a length that describe the same region of the RX buffer.\n\nPass rx_skb-\u003elen, the length of the subframe actually being parsed.",
  "id": "GHSA-c488-ccg3-wfcm",
  "modified": "2026-08-19T18:32:28Z",
  "published": "2026-08-15T15:30:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74488"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/25e5a3fe4f15e30f74eca42cbf3bcc3a3fbeda79"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3b02275833a0d3e6583627995d614fa99bdf364f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5a21ab03829cb6d2682c127f22e2b9cd63b4393f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/707664027bb9307f7268eda403af7c4ccd9b8644"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/99a948382af8a225e2d5e54a7052158cd6281cc6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a1f0f7dc7eb15754e6931b433edb7beb754c996a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c9dcfe6b8b71369e1d732e2ff622c3696a2f032c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ece2ebb34247d573142617dfc534a9dc11ba59be"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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