CVE-2026-72003wifi: brcmfmac: cyw: fix heap overflow on a short auth frame

Official description

In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: cyw: fix heap overflow on a short auth frame brcmf_notify_auth_frame_rx() takes the frame length from the firmware event and copies the frame body with the management header offset subtracted: u32 mgmt_frame_len = e->datalen - sizeof(struct brcmf_rx_mgmt_data); ... memcpy(&mgmt_frame->u, frame, mgmt_frame_len - offsetof(struct ieee80211_mgmt, u)); The only length check is e->datalen >= sizeof(*rxframe), so mgmt_frame_len can be anything from 0 up. offsetof(struct ieee80211_mgmt, u) is 24. When mgmt_frame_len is below that, the subtraction wraps as an unsigned value to a huge length. The memcpy then runs far past the kzalloc'd buffer. A malicious or malfunctioning AP can make the frame short during the external SAE auth exchange, so this is a remotely triggered heap overflow. Reject frames shorter than the management header offset before the copy.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/55b26abb1fa1ec406b3ad11b43c49c7624257565
• https://git.kernel.org/stable/c/185bb156c427d0f865d344a6d0eaa02c6d05cc57
• https://git.kernel.org/stable/c/240c8d2c717b3f8153e7e877b22a82518d78dbdc