CVE Catalog

CVE-2026-63869

HighCVSS 7.6
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.21%

11th percentile - higher than 11% of all known CVEs

Summary

In the Linux kernel's mac80211 subsystem, a vulnerability was found where the antenna index from the radiotap header is used directly as a shift count in a bit operation. This can cause undefined behavior reported by UBSAN.

Risk Assessment

An attacker with the ability to inject frames via a monitor interface could cause a system crash or unexpected kernel behavior, posing a risk to organizational stability and security.

Recommendation

Immediately update the Linux kernel to a version containing the fix that limits the antenna index to values 0 or 1.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: limit injected antenna index in ieee80211_parse_tx_radiotap When parsing the radiotap header of an injected frame, ieee80211_parse_tx_radiotap() uses the IEEE80211_RADIOTAP_ANTENNA value directly as a shift count: info->control.antennas |= BIT(*iterator.this_arg); *iterator.this_arg is an 8-bit value taken straight from the frame supplied by userspace, so BIT() can be asked to shift by up to 255. That is undefined behaviour on the unsigned long and is reported by UBSAN: UBSAN: shift-out-of-bounds in net/mac80211/tx.c:2174:30 shift exponent 235 is too large for 64-bit type 'unsigned long' Call Trace: ieee80211_parse_tx_radiotap+0xadb/0x1950 net/mac80211/tx.c:2174 ieee80211_monitor_start_xmit+0xb1f/0x1250 net/mac80211/tx.c:2451 ... packet_sendmsg+0x3eb6/0x50f0 net/packet/af_packet.c:3109 info->control.antennas is a 2-bit bitmap (u8 antennas:2), so only antenna indices 0 and 1 can ever be represented. Ignore any larger value instead of shifting out of bounds.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS