CVE-2026-43057

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxa0478d7e888028f85fa7785ea838ce0ca09398e2 < 2094a7cf91b71367b649f991aacc7b579f793d0baffected
LinuxLinux2156d9e9f2e483c8c3906c0ea57ea312c1424235 < ed71cf465c75f5688b07a35d373cd1d6b589c8eaaffected
LinuxLinux041e2f945f82fdbd6fff577b79c33469430297aa < 33670f780e0120c3dacda188c512bbffe0b6044caffected
LinuxLinux864e3396976ef41de6cc7bc366276bf4e084fff2 < a98b78116a27e2a57b696b569b2cb431c95cf9b6affected
LinuxLinux864e3396976ef41de6cc7bc366276bf4e084fff2 < 732fdeb2987c94b439d51f5cb9addddc2fc48c42affected
LinuxLinux864e3396976ef41de6cc7bc366276bf4e084fff2 < c4336a07eb6b2526dc2b62928b5104b41a7f81f5affected
LinuxLinux794ddbb7b63b6828c75967b9bcd43b086716e7a1affected
LinuxLinux6.1.149 < 6.1.168affected
LinuxLinux6.6.103 < 6.6.134affected
LinuxLinux6.12.44 < 6.12.81affected
LinuxLinux6.16.4 < 6.17affected
LinuxLinux6.17affected
LinuxLinux0 < 6.17unaffected
LinuxLinux6.1.168 <= 6.1.*unaffected
LinuxLinux6.6.134 <= 6.6.*unaffected
LinuxLinux6.12.81 <= 6.12.*unaffected
LinuxLinux6.18.22 <= 6.18.*unaffected
LinuxLinux6.19.12 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References