CVE-2023-54157: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-54157 is a use-after-free (UAF) vulnerability in the Linux kernel's Android Binder IPC driver, specifically in the binder_update_page_range() function. The flaw arises from a race condition between Binder's VMA access and munmap() operations, where alloc->vma can be freed while still being accessed. It was published on December 24, 2025, and affects multiple stable Linux kernel versions. The estimated CVSS severity is Medium (Feedly).

The root cause is a use-after-free condition (CWE-416) in the Linux kernel Binder driver. Commit 720c24192404 changed Binder to use mmap_lock read-lock (instead of write-lock) to protect alloc->vma in binder_update_page_range(). However, commit dd2283f2605e later changed munmap() to downgrade the mmap_lock to a read lock after detaching the VMA from the rbtree, then proceeds to tear down and free the VMA with only the read lock held. This creates a race window where Binder's read-locked access to alloc->vma in binder_update_page_range() can race with vm_area_free() in munmap(), resulting in a UAF. A KASAN trace demonstrating the issue shows a read of freed memory at vm_insert_page+0x7c/0x1f0 triggered by a server process (Feedly). The fix is a clean forward port from commit 015ac18be7de originally applied to the 5.10 stable branch, needed in mainline after the revert of commit a43cfc87caaf which had previously stopped saving a pointer to the VMA (Feedly).

Successful exploitation of this race condition can lead to kernel memory corruption via use-after-free, potentially enabling a local attacker to crash the system (denial of service) or escalate privileges. Because the vulnerability resides in the Binder IPC driver — a core component of Android and Linux inter-process communication — exploitation could allow a malicious application or process to gain elevated kernel-level access. The confidentiality, integrity, and availability of the affected system are all at risk if the UAF is weaponized for privilege escalation (Feedly).

The fix has been backported to multiple Linux kernel stable branches via commits 1bb8a65190d4, 931ea1ed31be, ca0cc0a9c6e5, and d1d8875c8c13 in the kernel stable tree (Kernel Git). Users should update to a patched kernel version as soon as their distribution makes it available. OpenSUSE has tracked this issue under bugzilla bug 1255705. No configuration-based workaround is known; applying the kernel patch is the recommended remediation.