CVE-2026-43057

High

In the Linux kernel, the following vulnerability has been resolved: net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback NETIF_F_IPV6_CSUM only advertises support for checksum offload of packets without IPv6 extension headers. Packets with extension headers must fall back onto software checksumming. Since TSO depends on checksum offload, those must revert to GSO. The below commit introduces that fallback. It always checks network header length. For tunneled packets, the inner header length must be checked instead. Extend the check accordingly. A special case is tunneled packets without inner IP protocol. Such as RFC 6951 SCTP in UDP. Those are not standard IPv6 followed by transport header either, so also must revert to the software GSO path.

Package Linux Kernel
Published 2026-05-01
Last modified 2026-05-06
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.5

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

Affected versions

Linux kernel versions 6.1.149, 6.6.103, 6.12.44, 6.16.4, 6.17 and later are affected. Fixed in 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12, 7.0 and their respective stable series.

Affected from
≥ 6.1.149 ≥ 6.6.103 ≥ 6.12.44 ≥ 6.16.4 ≥ 6.17
Fixed in
✓ 6.1.168 6.1.x ✓ 6.6.134 6.6.x ✓ 6.12.81 6.12.x ✓ 6.18.22 6.18.x ✓ 6.19.12 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43057 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

6 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2026-43057?

    CVE-2026-43057 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 . It affects Linux kernel versions from 6.1.149 onward and has been patched in 6.1.168, 6.6.134, 6.12.81 and others. CVE-2026-43057 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-43057?

    CVE-2026-43057 has a CVSS score of 7.5 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2026-43057?

    Yes — CVE-2026-43057 has been patched. Fixed versions include 6.1.168, 6.6.134, 6.12.81 and others. If you are running Linux kernel 6.1.149 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-43057 actively exploited?

    No — CVE-2026-43057 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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