CVE-2025-39891 wifi: mwifiex: Initialize the chan_stats array to zero
A local attacker can read uninitialized kernel memory via the mwifiex Wi-Fi driver, potentially exposing sensitive data.
- 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-2025-39891?
CVE-2025-39891 is a high-severity vulnerability in Debian Debian Linux, published on 1 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: mwifiex: Initialize the chan_stats array to zero
The adapter->chan_stats[] array is initialized in mwifiex_init_channel_scan_gap() with vmalloc(), which doesn't zero out memory. The array is filled in mwifiex_update_chan_statistics() and then the user can query the data in mwifiex_cfg80211_dump_survey().
There are two potential issues here. What if the user calls mwifiex_cfg80211_dump_survey() before the data has been filled in. Also the mwifiex_update_chan_statistics() function doesn't necessarily initialize the whole array. Since the array was not initialized at the start that could result in an information leak.
Also this array is pretty small. It's a maximum of 900 bytes so it's more appropriate to use kcalloc() instead vmalloc().
Which versions are affected by CVE-2025-39891?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39891?
Apply the vendor's patch.
Is CVE-2025-39891 being exploited?
There is no known exploitation of CVE-2025-39891 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-68007, AZL-75122, BELL-CVE-2025-39891, DEBIAN-CVE-2025-39891, GHSA-2237-jrrh-3624, ROOT-OS-DEBIAN-11-CVE-2025-39891 and 3 more.