CVE-2026-23154

Summary

In the Linux kernel, the following vulnerability has been resolved:

net: fix segmentation of forwarding fraglist GRO

This patch enhances GSO segment handling by properly checking the SKB_GSO_DODGY flag for frag_list GSO packets, addressing low throughput issues observed when a station accesses IPv4 servers via hotspots with an IPv6-only upstream interface.

Specifically, it fixes a bug in GSO segmentation when forwarding GRO packets containing a frag_list. The function skb_segment_list cannot correctly process GRO skbs that have been converted by XLAT, since XLAT only translates the header of the head skb. Consequently, skbs in the frag_list may remain untranslated, resulting in protocol inconsistencies and reduced throughput.

To address this, the patch explicitly sets the SKB_GSO_DODGY flag for GSO packets in XLAT's IPv4/IPv6 protocol translation helpers (bpf_skb_proto_4_to_6 and bpf_skb_proto_6_to_4). This marks GSO packets as potentially modified after protocol translation. As a result, GSO segmentation will avoid using skb_segment_list and instead falls back to skb_segment for packets with the SKB_GSO_DODGY flag. This ensures that only safe and fully translated frag_list packets are processed by skb_segment_list, resolving protocol inconsistencies and improving throughput when forwarding GRO packets converted by XLAT.

Affected Software

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

References

• https://git.kernel.org/stable/c/9122d7280b2303e835cdfec156bd932ac1f586ed
• https://git.kernel.org/stable/c/2cbef9ea5a0ac51863ede35c45f26931a85d3888
• https://git.kernel.org/stable/c/3e62db1e3140449608975e29e0979cc5f3b1cc07
• https://git.kernel.org/stable/c/3d48d59235c494d34e32052f768393111c0806ef
• https://git.kernel.org/stable/c/426ca15c7f6cb6562a081341ca88893a50c59fa2

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