Bug 2484451 (CVE-2026-46244) - CVE-2026-46244 kernel: netfilter: nft_inner: Fix IPv6 inner_thoff desync
Summary: CVE-2026-46244 kernel: netfilter: nft_inner: Fix IPv6 inner_thoff desync
Keywords:
Status: NEW
Alias: CVE-2026-46244
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-03 18:02 UTC by OSIDB Bzimport
Modified: 2026-06-03 19:49 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
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Description OSIDB Bzimport 2026-06-03 18:02:06 UTC
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.


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