CVE-2025-38606

Published Aug 19, 2025

Last updated a year ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: Avoid accessing uninitialized arvif->ar during beacon miss During beacon miss handling, ath12k driver iterates over active virtual interfaces (vifs) and attempts to access the radio object (ar) via arvif->deflink->ar. However, after commit aa80f12f3bed ("wifi: ath12k: defer vdev creation for MLO"), arvif is linked to a radio only after vdev creation, typically when a channel is assigned or a scan is requested. For P2P capable devices, a default P2P interface is created by wpa_supplicant along with regular station interfaces, these serve as dummy interfaces for P2P-capable stations, lack an associated netdev and initiate frequent scans to discover neighbor p2p devices. When a scan is initiated on such P2P vifs, driver selects destination radio (ar) based on scan frequency, creates a scan vdev, and attaches arvif to the radio. Once the scan completes or is aborted, the scan vdev is deleted, detaching arvif from the radio and leaving arvif->ar uninitialized. While handling beacon miss for station interfaces, P2P interface is also encountered in the vif iteration and ath12k_mac_handle_beacon_miss_iter() tries to dereference the uninitialized arvif->deflink->ar. Fix this by verifying that vdev is created for the arvif before accessing its ar during beacon miss handling and similar vif iterator callbacks. ========================================================================== wlp6s0: detected beacon loss from AP (missed 7 beacons) - probing KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 5 UID: 0 PID: 0 Comm: swapper/5 Not tainted 6.16.0-rc1-wt-ath+ #2 PREEMPT(full) RIP: 0010:ath12k_mac_handle_beacon_miss_iter+0xb5/0x1a0 [ath12k] Call Trace: __iterate_interfaces+0x11a/0x410 [mac80211] ieee80211_iterate_active_interfaces_atomic+0x61/0x140 [mac80211] ath12k_mac_handle_beacon_miss+0xa1/0xf0 [ath12k] ath12k_roam_event+0x393/0x560 [ath12k] ath12k_wmi_op_rx+0x1486/0x28c0 [ath12k] ath12k_htc_process_trailer.isra.0+0x2fb/0x620 [ath12k] ath12k_htc_rx_completion_handler+0x448/0x830 [ath12k] ath12k_ce_recv_process_cb+0x549/0x9e0 [ath12k] ath12k_ce_per_engine_service+0xbe/0xf0 [ath12k] ath12k_pci_ce_workqueue+0x69/0x120 [ath12k] process_one_work+0xe3a/0x1430 Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.4.1-00199-QCAHKSWPL_SILICONZ-1 Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00284.1-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
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