The Linux kernel's mac80211 wifi driver had a vulnerability in ieee80211_parse_tx_radiotap where the antenna index from a radiotap header was used directly as a shift count in a BIT() macro. Since the antenna index is an 8-bit value from userspace, it could be as large as 255, causing undefined behavior due to shifting beyond the size of an unsigned long. The antenna bitmap is only 2 bits wide, so only indices 0 and 1 are valid. The fix involves ignoring any antenna index values greater than 1 to avoid out-of-bounds shifts.

The vulnerability causes undefined behavior in kernel code due to out-of-bounds bit shifts, which can lead to kernel instability or crashes. There is no evidence of exploitation in the wild. The impact is primarily a potential denial of service or kernel panic triggered by malformed radiotap headers in injected wifi frames.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since this is a Linux kernel vulnerability, monitor for official kernel updates that address this issue and apply them promptly. Avoid using untrusted userspace tools that inject malformed radiotap frames until a fix is applied.