CVE-2026-64447

Published Jul 25, 2026

Last updated 2 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: staging: media: ipu7: fix double-free and use-after-free in error paths In both ipu7_isys_init() and ipu7_psys_init(), pdata is allocated and then passed to ipu7_bus_initialize_device(), which stores it in adev->pdata. The ipu7_bus_release() function frees adev->pdata when the device's reference count drops to zero. Two error paths incorrectly call kfree(pdata) after the device teardown has already freed it: 1. When ipu7_mmu_init() fails: put_device() is called, which drops the reference count to zero and triggers ipu7_bus_release() -> kfree(pdata). The subsequent kfree(pdata) is a double-free. 2. When ipu7_bus_add_device() fails: it calls auxiliary_device_uninit() internally, which calls put_device() -> ipu7_bus_release() -> kfree(pdata). The subsequent kfree(pdata) is again a double-free. Note that the kfree(pdata) when ipu7_bus_initialize_device() itself fails is correct, because in that case auxiliary_device_init() failed and the release function was never set up, so pdata must be freed manually. Additionally, the error code was not saved before calling put_device(), causing ERR_CAST() to dereference the already-freed adev pointer when constructing the return value. Fix this by saving the error from dev_err_probe() before put_device() and returning ERR_PTR() instead. Remove the redundant kfree(pdata) calls and fix the use-after-free in the return values of the two affected error paths.
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel

Risk scores

CVSS 3.1

Type
Secondary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-415

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