CVE-2026-46244

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_inner: Fix IPv6 inner_thoff desync In nft_inner_parse_l2l3(), when processing inner IPv6 packets, ipv6_find_hdr() correctly computes the transport header offset traversing all extension headers, but the result is immediately overwritten with nhoff + sizeof(_ip6h) (40 bytes), which only accounts for the IPv6 base header. This creates a desync between inner_thoff (wrong — points to extension header start) and l4proto (correct — e.g., IPPROTO_TCP), enabling transport header forgery and potential firewall bypass. This issue affects stable versions from Linux 6.2. For comparison, the normal (non-inner) IPv6 path correctly preserves ipv6_find_hdr()'s result. Removing the incorrect overwrite ensures that ipv6_find_hdr()'s calculated transport header offset is preserved, thereby fixing the desynchronization.

References

• https://git.kernel.org/stable/c/689bbf48c1f45130086ae1c46ab83ea4c753c601
• https://git.kernel.org/stable/c/870d59e2cf218e7418491e26bad768cb16654582
• https://git.kernel.org/stable/c/b6a91f68ebfed9c38e0e9150f58a9b85da07181c
• https://git.kernel.org/stable/c/c161ad9157f5a0429b5ff94d9770faf3bf48d273
• https://git.kernel.org/stable/c/d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce