# CVE-2022-49939: binder: fix UAF of ref->proc caused by race condition

> A race condition in the Linux kernel binder driver causes a use-after-free, potentially allowing local attackers to execute code or escalate privileges.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Jun 2025
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-49939, GHSA-6q3v-9ww3-wjw7, UBUNTU-CVE-2022-49939

## What is CVE-2022-49939?

CVE-2022-49939 is a high-severity use after free vulnerability in Linux kernel, published on 18 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

binder: fix UAF of ref->proc caused by race condition

A transaction of type BINDER_TYPE_WEAK_HANDLE can fail to increment the
reference for a node. In this case, the target proc normally releases
the failed reference upon close as expected. However, if the target is
dying in parallel the call will race with binder_deferred_release(), so
the target could have released all of its references by now leaving the
cleanup of the new failed reference unhandled.

The transaction then ends and the target proc gets released making the
ref->proc now a dangling pointer. Later on, ref->node is closed and we
attempt to take spin_lock(&ref->proc->inner_lock), which leads to the
use-after-free bug reported below. Let's fix this by cleaning up the
failed reference on the spot instead of relying on the target to do so.

  ==================================================================
  BUG: KASAN: use-after-free in _raw_spin_lock+0xa8/0x150
  Write of size 4 at addr ffff5ca207094238 by task kworker/1:0/590

  CPU: 1 PID: 590 Comm: kworker/1:0 Not tainted 5.19.0-rc8 #10
  Hardware name: linux,dummy-virt (DT)
  Workqueue: events binder_deferred_func
  Call trace:
   dump_backtrace.part.0+0x1d0/0x1e0
   show_stack+0x18/0x70
   dump_stack_lvl+0x68/0x84
   print_report+0x2e4/0x61c
   kasan_report+0xa4/0x110
   kasan_check_range+0xfc/0x1a4
   __kasan_check_write+0x3c/0x50
   _raw_spin_lock+0xa8/0x150
   binder_deferred_func+0x5e0/0x9b0
   process_one_work+0x38c/0x5f0
   worker_thread+0x9c/0x694
   kthread+0x188/0x190
   ret_from_fork+0x10/0x20

Weakness: CWE-416 (Use After Free), CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2022-49939?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49939?

Apply the vendor's patch.

## Is CVE-2022-49939 being exploited?

There is no known exploitation of CVE-2022-49939 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-49939 and fix it if it is affected.

What it is: CVE-2022-49939 is a high-severity use after free vulnerability in Linux kernel, published on 18 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-49939 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2022-49939/ (Markdown: https://insights.sbomify.com/CVE-2022-49939/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49939
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49939
- OSV: https://osv.dev/vulnerability/CVE-2022-49939

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49939/
Summaries are generated and may contain mistakes; the official description above is the record.