CVE-2021-46998: ethernet:enic: Fix a use after free bug in enic_hard_start_xmit

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-02-28 · updated 2026-08-04
Weakness: CWE-416

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.

Affected products

Linux kernel: from 4.16 before 4.19.191; from 4.20 before 5.4.120; from 5.5 before 5.10.38; from 5.11 before 5.11.22; from 5.12 before 5.12.5 — fixed in 4.19.191, 5.10.38, 5.11.22, 5.12.5, 5.4.120

How to fix

Upgrade to a fixed version: Linux kernel 4.19.191, 5.10.38, 5.11.22, 5.12.5. Check the vendor advisory for mitigations.

References

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