CVE-2026-68326

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

wifi: mwifiex: bound uAP association event IEs to the event buffer

mwifiex_process_uap_event() handles EVENT_UAP_STA_ASSOC by exposing the (re)association request IEs that the firmware copies into the event:

sinfo->assoc_req_ies = &event->data[len];
len = (u8 *)sinfo->assoc_req_ies - (u8 *)&event->frame_control;
sinfo->assoc_req_ies_len = le16_to_cpu(event->len) - (u16)len;

event->len is supplied by the device firmware and is never validated, and the subtraction is unchecked. assoc_req_ies points into adapter->event_body[MAX_EVENT_SIZE], a fixed-size array embedded in the kmalloc()d struct mwifiex_adapter.

On the ap_11n_enabled path mwifiex_set_sta_ht_cap() walks these IEs with cfg80211_find_ie(), whose for_each_element() loop dereferences each element header. A firmware-reported event->len larger than the bytes actually received makes assoc_req_ies_len describe IEs that extend past event_body, so the walk reads out of the adapter slab object, a slab-out-of-bounds read (KASAN: slab-out-of-bounds in cfg80211_find_ie). An event->len smaller than the header instead makes the int subtraction negative, which wraps to a huge size_t when stored in assoc_req_ies_len. The same length is handed to cfg80211_new_sta(), so a more modest over-claim can also copy stale event_body bytes into the NL80211_CMD_NEW_STATION notification.

A malicious or malfunctioning mwifiex device (USB/SDIO/PCIe) can deliver such an event while the interface is in AP/uAP mode.

Validate event->len before use: reject a length that underflows the header or that would place the IEs outside the event_body[] buffer the event was copied into. event->len here is struct mwifiex_assoc_event.len, a payload field internal to this event, not the transport frame length, so it is validated in this handler rather than at the generic MWIFIEX_TYPE_EVENT receive path, which only sees the event cause and the transport frame length. The bound is against event_body[MAX_EVENT_SIZE] rather than the actually-received length because the transports store the event differently (USB and SDIO leave the 4-byte event header in event_skb, PCIe strips it via skb_pull), whereas event_body is the single fixed buffer all of them copy the event into. This is the event-path analogue of the receive-path bounds checks added in commit 119585281617 (wifi: mwifiex: Fix OOB and integer underflow when rx packets).

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/1ae00b6d9a6c82eb3de151d9b04ed59e06cc100f
• https://git.kernel.org/stable/c/a3f47d7c75ddad1a14621a309286f9fae3cba191
• https://git.kernel.org/stable/c/a616616b938f7922a93e79bef16b4643c57c0922
• https://git.kernel.org/stable/c/ad26c75ae25749313248f06510ebe43b5bf4adcc
• https://git.kernel.org/stable/c/b6766d7ea43edf5de9d5a572bc58b631d09efe4b
• https://git.kernel.org/stable/c/d21464d93f8ba464dc3d7b4b31c6e0adcd9f659c
• https://git.kernel.org/stable/c/e7e93d3e8c240bdb70c41e79d169d74dfb442843
• https://git.kernel.org/stable/c/f0858bfc7d3cab411a447b88e3ef970e575032c9