CVE-2026-43057
Awaiting Analysis Awaiting Analysis - Queue
Linux Kernel IPv6 Checksum GSO Fallback Vulnerability

Publication date: 2026-05-01

Last updated on: 2026-05-06

Assigner: kernel.org

Description
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.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2026-05-01
Last Modified
2026-05-06
Generated
2026-05-07
AI Q&A
2026-05-01
EPSS Evaluated
2026-05-05
NVD
CVE-2026-43057
EUVD
EUVD-2026-26656
Affected Vendors & Products
Showing 17 associated CPEs
Vendor Product Version / Range
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel From 6.19 (inc) to 6.19.12 (exc)
linux linux_kernel From 6.1.149 (inc) to 6.1.168 (exc)
linux linux_kernel From 6.12.44 (inc) to 6.12.81 (exc)
linux linux_kernel From 6.16.4 (inc) to 6.17 (exc)
linux linux_kernel From 6.6.103 (inc) to 6.6.134 (exc)
linux linux_kernel From 6.17.1 (exc) to 6.18.22 (exc)
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability relates to how the Linux kernel handles tunneled IPv6 traffic with checksum offloading and segmentation offloading features. Specifically, the kernel did not correctly handle packets with IPv6 extension headers during checksum offload, which requires software fallback for such packets. The issue was that the kernel only checked the outer network header length, but for tunneled packets, it must check the inner header length instead. Additionally, special cases like tunneled packets without an inner IP protocol (e.g., RFC 6951 SCTP in UDP) were not properly handled and needed to revert to software processing. The vulnerability was fixed by introducing a fallback mechanism that correctly checks the inner header length and ensures proper software handling of these special tunneled packets.


How can this vulnerability impact me? :

If this vulnerability is present, tunneled IPv6 packets with extension headers or special inner protocols might not be processed correctly by the kernel's checksum and segmentation offloading mechanisms. This could lead to incorrect packet handling, potentially causing network communication issues such as dropped or corrupted packets, degraded network performance, or unexpected behavior in applications relying on tunneled IPv6 traffic.


Ask Our AI Assistant
Need more information? Ask your question to get an AI reply (Powered by our expertise)
0/70
EPSS Chart