CVE-2025-38450

Published Jul 25, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7925: prevent NULL pointer dereference in mt7925_sta_set_decap_offload() Add a NULL check for msta->vif before accessing its members to prevent a kernel panic in AP mode deployment. This also fix the issue reported in [1]. The crash occurs when this function is triggered before the station is fully initialized. The call trace shows a page fault at mt7925_sta_set_decap_offload() due to accessing resources when msta->vif is NULL. Fix this by adding an early return if msta->vif is NULL and also check wcid.sta is ready. This ensures we only proceed with decap offload configuration when the station's state is properly initialized. [14739.655703] Unable to handle kernel paging request at virtual address ffffffffffffffa0 [14739.811820] CPU: 0 UID: 0 PID: 895854 Comm: hostapd Tainted: G [14739.821394] Tainted: [C]=CRAP, [O]=OOT_MODULE [14739.825746] Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT) [14739.831577] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [14739.838538] pc : mt7925_sta_set_decap_offload+0xc0/0x1b8 [mt7925_common] [14739.845271] lr : mt7925_sta_set_decap_offload+0x58/0x1b8 [mt7925_common] [14739.851985] sp : ffffffc085efb500 [14739.855295] x29: ffffffc085efb500 x28: 0000000000000000 x27: ffffff807803a158 [14739.862436] x26: ffffff8041ececb8 x25: 0000000000000001 x24: 0000000000000001 [14739.869577] x23: 0000000000000001 x22: 0000000000000008 x21: ffffff8041ecea88 [14739.876715] x20: ffffff8041c19ca0 x19: ffffff8078031fe0 x18: 0000000000000000 [14739.883853] x17: 0000000000000000 x16: ffffffe2aeac1110 x15: 000000559da48080 [14739.890991] x14: 0000000000000001 x13: 0000000000000000 x12: 0000000000000000 [14739.898130] x11: 0a10020001008e88 x10: 0000000000001a50 x9 : ffffffe26457bfa0 [14739.905269] x8 : ffffff8042013bb0 x7 : ffffff807fb6cbf8 x6 : dead000000000100 [14739.912407] x5 : dead000000000122 x4 : ffffff80780326c8 x3 : 0000000000000000 [14739.919546] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffffff8041ececb8 [14739.926686] Call trace: [14739.929130] mt7925_sta_set_decap_offload+0xc0/0x1b8 [mt7925_common] [14739.935505] ieee80211_check_fast_rx+0x19c/0x510 [mac80211] [14739.941344] _sta_info_move_state+0xe4/0x510 [mac80211] [14739.946860] sta_info_move_state+0x1c/0x30 [mac80211] [14739.952116] sta_apply_auth_flags.constprop.0+0x90/0x1b0 [mac80211] [14739.958708] sta_apply_parameters+0x234/0x5e0 [mac80211] [14739.964332] ieee80211_add_station+0xdc/0x190 [mac80211] [14739.969950] nl80211_new_station+0x46c/0x670 [cfg80211] [14739.975516] genl_family_rcv_msg_doit+0xdc/0x150 [14739.980158] genl_rcv_msg+0x218/0x298 [14739.983830] netlink_rcv_skb+0x64/0x138 [14739.987670] genl_rcv+0x40/0x60 [14739.990816] netlink_unicast+0x314/0x380 [14739.994742] netlink_sendmsg+0x198/0x3f0 [14739.998664] __sock_sendmsg+0x64/0xc0 [14740.002324] ____sys_sendmsg+0x260/0x298 [14740.006242] ___sys_sendmsg+0xb4/0x110
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

nvd@nist.gov
CWE-476

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: cgroup: Avoid iteration of dying tasks with zero refcount The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()") extended the lifetime of tasks on the dying_tasks list. The iterators have provision to go through dying_tasks because of dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however, it was expected that such tasks can obtain a new reference (that is possible before cgroup_task_release()/put_task_struct_rcu_user()). The tasks after cgroup_task_release() and before cgroup_task_free() are subject to race when they may or may not have ->usage count > 0. The race window is between css_task_iter_next() invocations when css_set_lock is released and we may arrive at a new ->task_pos. The iterator should not attempt to resurrect tasks whose ->usage count dropped to zero. (When that happens, __put_task_struct_rcu_cb() is already imminent and the returned task_struct would could be used after free.) As for the fix, we cannot simply check the signal->live count of a task on the dying list because that won't distinguish regular zombies waiting to be reaped from RCU remnant tasks that are going to be free'd. Therefore add an extra check to rule out ->usage==0 tasks from any iteration. The repeat: loop in css_task_iter_advance() doesn't consider ->usage count, so add a new loop to css_task_iter_next() to skip de-used tasks on the dying_list. Rough illustration of the possible race R (reader of cgroup.procs) T (thread) L (group leader) --------------------------------- -------------------------------- -------------------------------- L exits, signal->live > 0 cgroup_task_dead(L) css_set_skip_task_iters() // skips only cset->tasks list_add_tail(&L->cg_list, &cset->dying_tasks) css_task_iter_next() take css_set_lock css_task_iter_advance() leader && signal->live != 0 => it->task_pos = &L->cg_list release css_set_lock T exits --signal->live == 0 cgroup_task_dead(T) // css_set_lock release_task(T) cgroup_task_release(T) release_task(L) // zap_leader cgroup_task_release(L) put_task_struct_rcu_user(L) ...RCU... put_task_struct(L) L->usage = 0 /* L still on dying_tasks */ ...RCU... __put_task_struct(L) css_task_iter_next() // another iteration take css_set_lock it->task_pos = &L->cg_list get_task_struct(L) => addition on 0 drop css_set_lock cgroup_task_free(L) css_set_skip_task_iters() // dying skip comes too late free_task(L) cgroup_procs_show() task_pid_vnr(L)•CVE-2026-98163