CVE-2025-39957 wifi: mac80211: increase scan_ies_len for S1G
A missing length check for S1G capability elements causes a buffer validation failure, preventing hardware scanning and causing a denial of service in the Linux kernel.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39957?
CVE-2025-39957 is a high-severity denial of service vulnerability in Linux kernel, published on 9 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: increase scan_ies_len for S1G
Currently the S1G capability element is not taken into account for the scan_ies_len, which leads to a buffer length validation failure in ieee80211_prep_hw_scan() and subsequent WARN in __ieee80211_start_scan(). This prevents hw scanning from functioning. To fix ensure we accommodate for the S1G capability length.
Which versions are affected by CVE-2025-39957?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-39957?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-39957 being exploited?
There is no known exploitation of CVE-2025-39957 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-68331, BELL-CVE-2025-39957, DEBIAN-CVE-2025-39957, GHSA-mx4j-wm6m-3mxr, ROOT-OS-DEBIAN-11-CVE-2025-39957, ROOT-OS-DEBIAN-12-CVE-2025-39957 and 4 more.