CVE-2025-71234

In the Linux kernel, the following vulnerability has been resolved:

wifi: rtl8xxxu: fix slab-out-of-bounds in rtl8xxxu_sta_add

The driver does not set hw->sta_data_size, which causes mac80211 to allocate insufficient space for driver private station data in __sta_info_alloc(). When rtl8xxxu_sta_add() accesses members of struct rtl8xxxu_sta_info through sta->drv_priv, this results in a slab-out-of-bounds write.

KASAN report on RISC-V (VisionFive 2) with RTL8192EU adapter:

BUG: KASAN: slab-out-of-bounds in rtl8xxxu_sta_add+0x31c/0x346 Write of size 8 at addr ffffffd6d3e9ae88 by task kworker/u16:0/12

Set hw->sta_data_size to sizeof(struct rtl8xxxu_sta_info) during probe, similar to how hw->vif_data_size is configured. This ensures mac80211 allocates sufficient space for the driver's per-station private data.

Tested on StarFive VisionFive 2 v1.2A board.

A slab out of bounds write can occur in the rtl8xxxu USB wifi driver because hw sta_data_size is not set and mac80211 allocates insufficient per station private storage for sta drv_priv. When rtl8xxxu_sta_add writes fields of struct rtl8xxxu_sta_info via sta drv_priv it can overwrite adjacent slab memory which can crash the kernel and may corrupt kernel state. For the CVSS the PR is L because the bug is typically triggered by local network configuration actions such as enabling the interface and associating stations and these operations commonly require CAP_NET_ADMIN. In some deployments the attacker may only need to be within wireless range if the device is operating as an access point and accepts associations which can make the trigger effectively remote over the air. Impact is at least denial of service. A conservative worst case also considers confidentiality and integrity impact because the flaw is a kernel memory overwrite.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.