CVE-2026-63869

wifi: mac80211: limit injected antenna index in ieee80211_parse_tx_radiotap

Published Jul 19, 2026 CVSS 3.1 · 7.6 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8726-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8727-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8760-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8726-2 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8726-3 Linux kernel (IBM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8800-1 Linux kernel (NVIDIA BaseOS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8760-2 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8726-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-3 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-8903-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8904-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8905-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8906-1 Linux kernel (IBM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8903-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8905-2 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-1284
CPEs cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:*
Type Values Removed Values Added
Weaknesses CWE-190
Type Values Removed Values Added
Weaknesses CWE-190
CWE-839
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.6, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L'}

Type Values Removed Values Added
Description 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.
Title wifi: mac80211: limit injected antenna index in ieee80211_parse_tx_radiotap
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 8:17 PM
Reserved
Jul 19, 2026, 7:54 AM
Status
Analyzed
Published
Jul 19, 2026, 3:16 PM
Modified
Oct 26, 2026, 4:42 PM
Severity
Low
Public date
Jul 19, 2026, 12:00 AM