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

net: gso: fix tcp fraglist segmentation after pull from frag_list

Detect tcp gso fraglist skbs with corrupted geometry (see below) and
pass these to skb_segment instead of skb_segment_list, as the first
can segment them correctly.

Valid SKB_GSO_FRAGLIST skbs
- consist of two or more segments
- the head_skb holds the protocol headers plus first gso_size
- one or more frag_list skbs hold exactly one segment
- all but the last must be gso_size

Optional datapath hooks such as NAT and BPF (bpf_skb_pull_data) can
modify these skbs, breaking these invariants.

In extreme cases they pull all data into skb linear. For TCP, this
causes a NULL ptr deref in __tcpv4_gso_segment_list_csum at
tcp_hdr(seg->next).

Detect invalid geometry due to pull, by checking head_skb size.
Don't just drop, as this may blackhole a destination. Convert to be
able to pass to regular skb_segment.

Approach and description based on a patch by Willem de Bruijn.

kernel.org https://git.kernel.org/stable/c/17bd3bd82f9f79f3feba15476c2b2c95a9b11ff8 [No types assigned]

kernel.org https://git.kernel.org/stable/c/2d4a83a44428de45bfe9dccb0192a3711d1097e0 [No types assigned]

kernel.org https://git.kernel.org/stable/c/3fdd8c83e83fa5e82f1b5585245c51e0355c9f46 [No types assigned]