CVE-2023-54157

None

CVSS

—

EPSS

0.1%

Published

Dec 24, 2025

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A race condition in the kernel's binder driver can let one operation free memory that another operation is still using, risking system crashes or security bypasses.

Exploitation: Local Privilege
Attacker needs: Local User
Complexity: Moderate
Impact: Privilege Gain
Component: OS kernel
Class: Memory Corruption
Remediation: Patch
Effort: Medium
Patch risk: Low

What it actually does

Use-after-free of alloc->vma in binder_update_page_range() due to insufficient mmap locking allowing munmap() to free the VMA under read lock.

Why it matters to the business

Kernel memory corruption or crashes on systems using the binder driver, potentially leading to denial of service or escalation of privileges; high urgency for Android and embedded Linux deployments despite low EPSS given the 308-day window since publication.

How an attack unfolds

An attacker with local access triggers concurrent binder transactions and munmap operations on the same mapping, racing the read-locked vma access in binder_update_page_range() against vm_area_free() to trigger the UAF shown in the KASAN trace.

How to fix it

Upgrade the Linux kernel to a version containing commit 1bb8a65190d45cd5c7dbc85e29b9102110cd6be6 or later; the fix restores the mmap write lock inside binder_update_page_range() while relying on the existing alloc->mutex serialization.

How to confirm the fix worked

Confirm the running kernel contains the fix commit; attempt to reproduce the original KASAN trace under concurrent munmap and binder load to verify absence of the race.

Typical attack path

Obtain local code execution on the target system
Map a region used by binder and start a transaction
Concurrently issue munmap on the same region from another thread
Trigger binder_update_page_range() to dereference the freed vma
Exploit the resulting UAF for memory corruption or crash

How to detect it

Search kernel logs and KASAN reports for use-after-free traces involving vm_insert_page, binder_update_page_range, and munmap sequences; correlate with binder_ioctl calls under high munmap activity.

BUG: KASAN: use-after-free in vm_insert_page
binder_update_page_range+0x278
vm_area_free+0x1c

What your security team should do

Prioritize kernel updates on all Android and binder-using systems within the next patch cycle
Monitor for binder-related kernel oops or KASAN reports in production logs
Review downstream dependents of the affected stable trees for backport inclusion

The record

In the Linux kernel, the following vulnerability has been resolved: binder: fix UAF of alloc->vma in race with munmap() [ cmllamas: clean forward port from commit 015ac18be7de ("binder: fix UAF of alloc->vma in race with munmap()") in 5.10 stable. It is needed in mainline after the revert of commit a43cfc87caaf ("android: binder: stop saving a pointer to the VMA") as pointed out by Liam. The commit log and tags have been tweaked to reflect this. ] In commit 720c24192404 ("ANDROID: binder: change down_write to down_read") binder assumed the mmap read lock is sufficient to protect alloc->vma inside binder_update_page_range(). This used to be accurate until commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap"), which now downgrades the mmap_lock after detaching the vma from the rbtree in munmap(). Then it proceeds to teardown and free the vma with only the read lock held. This means that accesses to alloc->vma in binder_update_page_range() now will race with vm_area_free() in munmap() and can cause a UAF as shown in the following KASAN trace: ================================================================== BUG: KASAN: use-after-free in vm_insert_page+0x7c/0x1f0 Read of size 8 at addr ffff16204ad00600 by task server/558 CPU: 3 PID: 558 Comm: server Not tainted 5.10.150-00001-gdc8dcf942daa #1 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x0/0x2a0 show_stack+0x18/0x2c dump_stack+0xf8/0x164 print_address_description.constprop.0+0x9c/0x538 kasan_report+0x120/0x200 __asan_load8+0xa0/0xc4 vm_insert_page+0x7c/0x1f0 binder_update_page_range+0x278/0x50c binder_alloc_new_buf+0x3f0/0xba0 binder_transaction+0x64c/0x3040 binder_thread_write+0x924/0x2020 binder_ioctl+0x1610/0x2e5c __arm64_sys_ioctl+0xd4/0x120 el0_svc_common.constprop.0+0xac/0x270 do_el0_svc+0x38/0xa0 el0_svc+0x1c/0x2c el0_sync_handler+0xe8/0x114 el0_sync+0x180/0x1c0 Allocated by task 559: kasan_save_stack+0x38/0x6c __kasan_kmalloc.constprop.0+0xe4/0xf0 kasan_slab_alloc+0x18/0x2c kmem_cache_alloc+0x1b0/0x2d0 vm_area_alloc+0x28/0x94 mmap_region+0x378/0x920 do_mmap+0x3f0/0x600 vm_mmap_pgoff+0x150/0x17c ksys_mmap_pgoff+0x284/0x2dc __arm64_sys_mmap+0x84/0xa4 el0_svc_common.constprop.0+0xac/0x270 do_el0_svc+0x38/0xa0 el0_svc+0x1c/0x2c el0_sync_handler+0xe8/0x114 el0_sync+0x180/0x1c0 Freed by task 560: kasan_save_stack+0x38/0x6c kasan_set_track+0x28/0x40 kasan_set_free_info+0x24/0x4c __kasan_slab_free+0x100/0x164 kasan_slab_free+0x14/0x20 kmem_cache_free+0xc4/0x34c vm_area_free+0x1c/0x2c remove_vma+0x7c/0x94 __do_munmap+0x358/0x710 __vm_munmap+0xbc/0x130 __arm64_sys_munmap+0x4c/0x64 el0_svc_common.constprop.0+0xac/0x270 do_el0_svc+0x38/0xa0 el0_svc+0x1c/0x2c el0_sync_handler+0xe8/0x114 el0_sync+0x180/0x1c0 [...] ================================================================== To prevent the race above, revert back to taking the mmap write lock inside binder_update_page_range(). One might expect an increase of mmap lock contention. However, binder already serializes these calls via top level alloc->mutex. Also, there was no performance impact shown when running the binder benchmark tests.

Affected packages

Ecosystem	Package	Introduced	Fixed
Linux	Kernel	4.20.0	5.15.115