CVE-2025-39957: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-39957 is a vulnerability discovered in the Linux kernel's wifi subsystem, specifically in the mac80211 component. The vulnerability was published on October 9, 2025, and affects the handling of S1G capability elements in wireless scanning functionality (NVD, RedHat).

The vulnerability stems from the S1G capability element not being taken into account for the scanieslen calculation, which results in a buffer length validation failure in ieee80211prephwscan() function and subsequent WARN condition in _ieee80211startscan(). The vulnerability has been assigned a CVSS v3.1 base score of 7.0 with the vector string CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (RedHat).

The primary impact of this vulnerability is the prevention of hardware scanning functionality in affected systems. When triggered, the vulnerability causes a buffer length validation failure which disrupts the normal operation of wireless network scanning capabilities (NVD).

The vulnerability has been resolved by ensuring accommodation for the S1G capability length in the scanieslen calculation. Fixed versions are available in the Linux kernel, with various distributions providing updated packages. For instance, Debian has fixed this in version 6.16.9-1 and later (Debian).