CVE-2026-46244 netfilter: nft_inner: Fix IPv6 inner_thoff desync
A logic error in Linux kernel netfilter allows attackers to bypass firewall rules by forging transport headers in inner IPv6 packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46244?
CVE-2026-46244 is a critical vulnerability in Linux kernel, published on 3 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-46244?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46244?
Apply the vendor's patch.
Is CVE-2026-46244 being exploited?
There is no known exploitation of CVE-2026-46244 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-89357, BELL-CVE-2026-46244, DEBIAN-CVE-2026-46244, GHSA-fgx8-r5g7-5cr9, ROOT-OS-DEBIAN-13-CVE-2026-46244, ROOT-OS-UBUNTU-2404-CVE-2026-46244 and 1 more.