Critical · published June 3, 2026
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.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 6.2, < 6.6.142 | 6.6.142 |
| linux/linux_kernel | ≥ 6.7, < 6.12.92 | 6.12.92 |
| linux/linux_kernel | ≥ 6.13, < 6.18.34 | 6.18.34 |
| linux/linux_kernel | ≥ 6.19, < 7.0.11 | 7.0.11 |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |