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Advisory severityHigh7.6Red Hat Linux

High [CVE-2026-63869] limit injected antenna index in ieee80211_parse_tx_radiotap

This high-severity Red Hat Linux advisory covers CVE-2026-63869 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat package: kernel.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-63869 Source published Source updated

VulniPulse record published Record updated

CVE-2026-63869
Affected products & platforms
Red Hat LinuxLinux Kernel
Open source advisory

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Summary

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. This vulnerability allows an attacker to cause undefined behavior by injecting a specially crafted frame with an invalid radiotap header.

This can lead to system instability or a denial of service (DoS), potentially causing the system to crash. Red Hat severity: Important — CVSS 7.6 (CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L).

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · high-confidence parse· fetched 7 days ago·verify at source

Fixed versions
  • kernel-0:6.12.0-211.56.1.el10_2
  • kernel-0:5.14.0-687.49.1.el9_8
  • RHSA-2026:68507
  • RHSA-2026:68570

Official advisory · high-confidence parse· fetched 7 days ago·verify at source

Mitigation

Upgrade to a fixed release: kernel-0:6.12.0-211.56.1.el10_2, kernel-0:5.14.0-687.49.1.el9_8, RHSA-2026:68507, RHSA-2026:68570. That is the remediation for this advisory.

The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.

Official advisory · high-confidence parse· fetched 7 days ago·verify at source

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