CVE-2024-56638

High

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_inner: incorrect percpu area handling under softirq Softirq can interrupt ongoing packet from process context that is walking over the percpu area that contains inner header offsets. Disable bh and perform three checks before restoring the percpu inner header offsets to validate that the percpu area is valid for this skbuff: 1) If the NFT_PKTINFO_INNER_FULL flag is set on, then this skbuff has already been parsed before for inner header fetching to register. 2) Validate that the percpu area refers to this skbuff using the skbuff pointer as a cookie. If there is a cookie mismatch, then this skbuff needs to be parsed again. 3) Finally, validate if the percpu area refers to this tunnel type. Only after these three checks the percpu area is restored to a on-stack copy and bh is enabled again. After inner header fetching, the on-stack copy is stored back to the percpu area.

Package Linux Kernel
Published 2024-12-27
Last modified 2025-10-07
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 6.2 and later are affected. Fixed in 6.6.66, 6.12.5, 6.13 and their respective stable series.

Affected from
≥ 6.2
Fixed in
✓ 6.6.66 6.6.x ✓ 6.12.5 6.12.x ✓ 6.13

References

The following references provide additional information about CVE-2024-56638 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Frequently asked questions

  • What is CVE-2024-56638?

    CVE-2024-56638 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 6.2 onward and has been patched in 6.6.66, 6.12.5 and 6.13. CVE-2024-56638 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2024-56638?

    CVE-2024-56638 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2024-56638?

    Yes — CVE-2024-56638 has been patched. Fixed versions include 6.6.66, 6.12.5 and 6.13. If you are running Linux kernel 6.2 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2024-56638 actively exploited?

    No — CVE-2024-56638 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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