CVE-2022-50240: android: binder: stop saving a pointer to the VMA

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-09-15 · updated 2026-08-04
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: android: binder: stop saving a pointer to the VMA Do not record a pointer to a VMA outside of the mmap_lock for later use. This is unsafe and there are a number of failure paths *after* the recorded VMA pointer may be freed during setup. There is no callback to the driver to clear the saved pointer from generic mm code. Furthermore, the VMA pointer may become stale if any number of VMA operations end up freeing the VMA so saving it was fragile to being with. Instead, change the binder_alloc struct to record the start address of the VMA and use vma_lookup() to get the vma when needed. Add lockdep mmap_lock checks on updates to the vma pointer to ensure the lock is held and depend on that lock for synchronization of readers and writers - which was already the case anyways, so the smp_wmb()/smp_rmb() was not necessary. [akpm@linux-foundation.org: fix drivers/android/binder_alloc_selftest.c]

Affected products

Linux kernel: from 4.20 before 5.4.224; from 5.5 before 5.10.154; from 5.11 before 5.15.61; from 5.16 before 5.18.18; from 5.19 before 5.19.2 — fixed in 5.10.154, 5.15.61, 5.18.18, 5.19.2, 5.4.224

How to fix

Upgrade to a fixed version: Linux kernel 5.10.154, 5.15.61, 5.18.18, 5.19.2. Check the vendor advisory for mitigations.

References

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