Advisory [CVE-2026-64445] fix WEP length underflow and OOB read in OnAuth

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs: fix WEP length underflow and OOB read in OnAuth() OnAuth() has two bugs in the shared-key authentication path. When the Privacy bit is set, rtw_wep_decrypt() is called without verifying that the frame is long enough to contain a valid WEP IV and ICV.

Inside rtw_wep_decrypt(), length is computed as: length = len - WLAN_HDR_A3_LEN - iv_len and then passed as (length - 4) to crc32_le(). If len is less than WLAN_HDR_A3_LEN + iv_len + icv_len (32 bytes), length - 4 is negative and, after the implicit cast to size_t, causes crc32_le() to read far beyond the frame buffer.

Add a minimum length check before accessing the IV field and calling the decryption path. When processing a seq=3 response, rtw_get_ie() stores the Challenge Text IE length in ie_len, but the subsequent memcmp() always reads 128 bytes regardless of ie_len.

IEEE 802.11 mandates a challenge text of exactly 128 bytes; reject any IE whose length field differs, matching the check already applied to OnAuthClient(). A flaw was found in the `rtl8723bs` Wi-Fi driver within the Linux kernel.

During shared-key authentication, an attacker on an adjacent network could send a specially crafted frame.