CVE-2025-71127: wifi: mac80211: Discard Beacon frames to non-broadcast address
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: Discard Beacon frames to non-broadcast address
Beacon frames are required to be sent to the broadcast address, see IEEE Std 802.11-2020, 11.1.3.1 ("The Address 1 field of the Beacon .. frame shall be set to the broadcast address"). A unicast Beacon frame might be used as a targeted attack to get one of the associated STAs to do something (e.g., using CSA to move it to another channel). As such, it is better have strict filtering for this on the received side and discard all Beacon frames that are sent to an unexpected address.
This is even more important for cases where beacon protection is used. The current implementation in mac80211 is correctly discarding unicast Beacon frames if the Protected Frame bit in the Frame Control field is set to 0. However, if that bit is set to 1, the logic used for checking for configured BIGTK(s) does not actually work. If the driver does not have logic for dropping unicast Beacon frames with Protected Frame bit 1, these frames would be accepted in mac80211 processing as valid Beacon frames even though they are not protected. This would allow beacon protection to be bypassed. While the logic for checking beacon protection could be extended to cover this corner case, a more generic check for discard all Beacon frames based on A1=unicast address covers this without needing additional changes.
Address all these issues by dropping received Beacon frames if they are sent to a non-broadcast address.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
Drop received IEEE 802.11 Beacon frames if the Beacon Frame Control 'Protected Frame' bit handling is not correct for the expected address: explicitly enforce strict filtering for unicast Beacon frames on the receive side (i.e., discard Beacon frames when Address 1 (A1) is a unicast address or otherwise not the broadcast address as required by IEEE Std 802.11-2020, 11.1.3.1).
Event History
Frequently Asked Questions
What is the severity of CVE-2025-71127?
CVE-2025-71127 is classified as a medium severity vulnerability.
How do I fix CVE-2025-71127?
To fix CVE-2025-71127, update your Linux kernel to the latest stable version as provided by your distribution.
What systems are affected by CVE-2025-71127?
CVE-2025-71127 affects the Linux kernel implementations that handle wifi operations utilizing the mac80211 module.
What type of vulnerability is CVE-2025-71127?
CVE-2025-71127 is a vulnerability related to the improper handling of Beacon frames in wireless communications.
Can CVE-2025-71127 be exploited remotely?
Yes, CVE-2025-71127 could potentially be exploited remotely due to its nature involving wireless network communication.