CVE-2026-64124

Published Jul 19, 2026

Last updated 2 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: net: devmem: reject dma-buf bind with non-page-aligned size or SG length net_devmem_bind_dmabuf() trusts dmabuf->size and sg_dma_len() to be PAGE_SIZE multiples without checking: - tx_vec is sized dmabuf->size / PAGE_SIZE, and net_devmem_get_niov_at() only bounds-checks virt_addr < dmabuf->size before indexing tx_vec[virt_addr / PAGE_SIZE]. With size = N*PAGE_SIZE + r (1 <= r < PAGE_SIZE), sendmsg() at iov_base = N*PAGE_SIZE passes the bound check and reads tx_vec[N] -- one past. - owner->area.num_niovs = len / PAGE_SIZE while gen_pool_add_owner() covers the full byte len, so a non-page-multiple non-final sg desyncs num_niovs from the gen_pool region for every later sg, on both RX and TX. dma-buf does not require page-aligned sizes, so the bind path has to enforce what its own indexing assumes. Reject both with -EINVAL. The size check is TX-only (only tx_vec is sized off dmabuf->size); the SG-length check covers both directions.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Secondary
Base score
8.8
Impact score
6
Exploitability score
2
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

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