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Review reviewHigh

CVE-2021-46998

Linux Linux, linux kernel

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.

CVSS
7.8
EPSS
0.24%
15.4% percentile
CISA KEV
Not listed
Published
2024.02.28
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.24%
Technical severityCVSS 7.8

Vulnerability overview

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 product and versions

Product
Linux Linux, linux kernel
Affected versions
>= fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 < 25a87b1f566b5eb2af2857a928f0e2310d900976, >= fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 < f7f6f07774091a6ddd98500b85386c3c6afb30d3, >= fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 < 7afdd6aba95c8a526038e7abe283eeac3e4320f1, >= fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 < 6892396ebf04ea2c021d80e10f4075e014cd7cc3, >= fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 < d90529392aaf498dafa95d212295d64b2cea4e24, >= fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 < 643001b47adc844ae33510c4bb93c236667008a3, >= 4.16, >= 4.16 < 4.19.191, >= 4.20 < 5.4.120, >= 5.5 < 5.10.38, >= 5.11 < 5.11.22, >= 5.12 < 5.12.5
Fixed versions
4.19.191, 5.4.120, 5.10.38, 5.11.22, 5.12.5

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416
CVE-2021-46998 — Linux Linux, linux kernel | SECUFOCUS NOW