CVE-2026-64469

Status: UPDATED  |  Advisory ID: CVE-2026-64469

Key Details

Affected Products, Subsystems & Sectors

What to Know

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

binder: fix UAF in binder_thread_release()

When a thread exits, binder_thread_release() walks its transaction stack

to clear the t->from and t->to_proc that correspond with the exiting

thread. However, a process dying in parallel might attempt to kfree some

of these transactions. And if one of them has no associated t->to_proc,

the t->to_proc->inner_lock will not be acquired.

This means that transaction accesses in binder_thread_release() after

t->to_proc has been cleared might race with binder_free_transaction()

and cause a use-after-free error as reported by KASAN:

==================================================================

BUG: KASAN: slab-use-after-free in binder_thread_release+0x5d0/0x798

Write of size 8 at addr ffff000016627500 by task X/715

CPU: 17 UID: 0 PID: 715 Comm: X Not tainted 7.1.0-rc5-00149-g8fde5d1d47f6 #30 PREEMPT

Hardware name: linux,dummy-virt (DT)

Call trace:

binder_thread_release+0x5d0/0x798

binder_ioctl+0x12c0/0x299c

[...]

Allocated by task 717 on cpu 18 at 67.267803s:

__kasan_kmalloc+0xa0/0xbc

__kmalloc_cache_noprof+0x174/0x444

binder_transaction+0x554/0x8150

binder_thread_write+0xa30/0x4354

binder_ioctl+0x20f0/0x299c

[...]

Freed by task 202 on cpu 18 at 90.416221s:

__kasan_slab_free+0x58/0x80

kfree+0x1a0/0x4a4

binder_free_transaction+0x150/0x294

binder_send_failed_reply+0x398/0x6d8

binder_release_work+0x3e4/0x4ec

binder_deferred_func+0xbd8/0x104c

[...]

==================================================================

In order to avoid this, make sure that binder_free_transaction() reads

the t->to_proc under the transaction lock. This will serialize the

transaction release with the accesses in binder_thread_release(). Plus,

it matches the documented locking rules for @to_proc. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References