Description
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.
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.
Published:
2026-08-15
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
||||||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No remediation available yet.
Tracking
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Advisories
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References
History
Sat, 15 Aug 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | wifi: mwifiex: use the subframe length when parsing A-MSDU TDLS frames | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-15T12:27:18.867Z
Reserved: 2026-08-15T05:44:03.905Z
Link: CVE-2026-74488
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-15T13:17:53.690
Modified: 2026-08-15T13:17:53.690
Link: CVE-2026-74488
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.