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Linux Kernel: Accessing Stale Data Can Crash System
CVE-2026-23184
Summary
A bug in the Linux kernel's binder system can cause the system to crash when it tries to access data that has already been freed. This happens when a frozen transaction is sent to a target, and the system continues to try to access the data after it has been thawed. Affected users should update their Linux kernel to the fixed version to prevent potential crashes.
Original title
In the Linux kernel, the following vulnerability has been resolved:
binder: fix UAF in binder_netlink_report()
Oneway transactions sent to frozen targets via binder_proc_transaction()
return a BR...
Original description
In the Linux kernel, the following vulnerability has been resolved:
binder: fix UAF in binder_netlink_report()
Oneway transactions sent to frozen targets via binder_proc_transaction()
return a BR_TRANSACTION_PENDING_FROZEN error but they are still treated
as successful since the target is expected to thaw at some point. It is
then not safe to access 't' after BR_TRANSACTION_PENDING_FROZEN errors
as the transaction could have been consumed by the now thawed target.
This is the case for binder_netlink_report() which derreferences 't'
after a pending frozen error, as pointed out by the following KASAN
report:
==================================================================
BUG: KASAN: slab-use-after-free in binder_netlink_report.isra.0+0x694/0x6c8
Read of size 8 at addr ffff00000f98ba38 by task binder-util/522
CPU: 4 UID: 0 PID: 522 Comm: binder-util Not tainted 6.19.0-rc6-00015-gc03e9c42ae8f #1 PREEMPT
Hardware name: linux,dummy-virt (DT)
Call trace:
binder_netlink_report.isra.0+0x694/0x6c8
binder_transaction+0x66e4/0x79b8
binder_thread_write+0xab4/0x4440
binder_ioctl+0x1fd4/0x2940
[...]
Allocated by task 522:
__kmalloc_cache_noprof+0x17c/0x50c
binder_transaction+0x584/0x79b8
binder_thread_write+0xab4/0x4440
binder_ioctl+0x1fd4/0x2940
[...]
Freed by task 488:
kfree+0x1d0/0x420
binder_free_transaction+0x150/0x234
binder_thread_read+0x2d08/0x3ce4
binder_ioctl+0x488/0x2940
[...]
==================================================================
Instead, make a transaction copy so the data can be safely accessed by
binder_netlink_report() after a pending frozen error. While here, add a
comment about not using t->buffer in binder_netlink_report().
binder: fix UAF in binder_netlink_report()
Oneway transactions sent to frozen targets via binder_proc_transaction()
return a BR_TRANSACTION_PENDING_FROZEN error but they are still treated
as successful since the target is expected to thaw at some point. It is
then not safe to access 't' after BR_TRANSACTION_PENDING_FROZEN errors
as the transaction could have been consumed by the now thawed target.
This is the case for binder_netlink_report() which derreferences 't'
after a pending frozen error, as pointed out by the following KASAN
report:
==================================================================
BUG: KASAN: slab-use-after-free in binder_netlink_report.isra.0+0x694/0x6c8
Read of size 8 at addr ffff00000f98ba38 by task binder-util/522
CPU: 4 UID: 0 PID: 522 Comm: binder-util Not tainted 6.19.0-rc6-00015-gc03e9c42ae8f #1 PREEMPT
Hardware name: linux,dummy-virt (DT)
Call trace:
binder_netlink_report.isra.0+0x694/0x6c8
binder_transaction+0x66e4/0x79b8
binder_thread_write+0xab4/0x4440
binder_ioctl+0x1fd4/0x2940
[...]
Allocated by task 522:
__kmalloc_cache_noprof+0x17c/0x50c
binder_transaction+0x584/0x79b8
binder_thread_write+0xab4/0x4440
binder_ioctl+0x1fd4/0x2940
[...]
Freed by task 488:
kfree+0x1d0/0x420
binder_free_transaction+0x150/0x234
binder_thread_read+0x2d08/0x3ce4
binder_ioctl+0x488/0x2940
[...]
==================================================================
Instead, make a transaction copy so the data can be safely accessed by
binder_netlink_report() after a pending frozen error. While here, add a
comment about not using t->buffer in binder_netlink_report().
Published: 14 Feb 2026 · Updated: 10 Mar 2026 · First seen: 6 Mar 2026