UBUNTU-CVE-2026-46244
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.
02 / AFFECTED SOFTWARE
Affected packages
12 explicit affected versions
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10 explicit affected versions
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40 explicit affected versions
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33 explicit affected versions
23 explicit affected versions
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12 explicit affected versions
9 explicit affected versions
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16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
49 explicit affected versions
14 explicit affected versions
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9 explicit affected versions
16 explicit affected versions
11 explicit affected versions
38 explicit affected versions
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13 explicit affected versions
6 explicit affected versions
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4 explicit affected versions
8 explicit affected versions
1 explicit affected versions
6 explicit affected versions
13 explicit affected versions
43 explicit affected versions
13 explicit affected versions
10 explicit affected versions
8 explicit affected versions
44 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
13 explicit affected versions
11 explicit affected versions
1 explicit affected versions
18 explicit affected versions
3 explicit affected versions
38 explicit affected versions
11 explicit affected versions
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50 explicit affected versions
6 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/b6a91f68ebfed9c38e0e9150f58a9b85da07181c
- https://ubuntu.com/security/CVE-2026-46244
- https://ubuntu.com/security/notices/USN-8488-1
- https://ubuntu.com/security/notices/USN-8488-2
- https://ubuntu.com/security/notices/USN-8489-1
- https://ubuntu.com/security/notices/USN-8490-1
- https://ubuntu.com/security/notices/USN-8490-2
- https://ubuntu.com/security/notices/USN-8491-1
- https://ubuntu.com/security/notices/USN-8492-1
- https://ubuntu.com/security/notices/USN-8492-2
- https://ubuntu.com/security/notices/USN-8492-3
- https://ubuntu.com/security/notices/USN-8492-4
- https://ubuntu.com/security/notices/USN-8492-5
- https://ubuntu.com/security/notices/USN-8497-1
- https://ubuntu.com/security/notices/USN-8498-1
- https://ubuntu.com/security/notices/USN-8499-1
- https://ubuntu.com/security/notices/USN-8507-1
- https://ubuntu.com/security/notices/USN-8508-1
- https://ubuntu.com/security/notices/USN-8545-1
- https://ubuntu.com/security/notices/USN-8546-1
- https://ubuntu.com/security/notices/USN-8569-1
- https://ubuntu.com/security/notices/USN-8603-1
- https://ubuntu.com/security/notices/USN-8604-1
- https://ubuntu.com/security/notices/USN-8605-1
- https://ubuntu.com/security/notices/USN-8606-1
- https://ubuntu.com/security/notices/USN-8607-1
- https://ubuntu.com/security/notices/USN-8609-1
- https://ubuntu.com/security/notices/USN-8619-1
- https://www.cve.org/CVERecord?id=CVE-2026-46244