Critical 10.0Published Apr 16, 2025

CVE-2025-22021netfilter: socket: Lookup orig tuple for IPv6 SNAT

Updated under an hour ago (Oct 28, 2026, 7:10 AM ET)

Does this affect you?

It affects Linux and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for Linux

Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: netfilter: socket: Lookup orig tuple for IPv6 SNAT nf_sk_lookup_slow_v4 does the conntrack lookup for IPv4 packets to restore the original 5-tuple in case of SNAT, to be able to find the right socket (if any). Then socket_match() can correctly check whether the socket was transparent. However, the IPv6 counterpart (nf_sk_lookup_slow_v6) lacks this conntrack lookup, making xt_socket fail to match on the socket when the packet was SNATed. Add the same logic to nf_sk_lookup_slow_v6. IPv6 SNAT is used in Kubernetes clusters for pod-to-world packets, as pods' addresses are in the fd00::/8 ULA subnet and need to be replaced with the node's external address. Cilium leverages Envoy to enforce L7 policies, and Envoy uses transparent sockets. Cilium inserts an iptables prerouting rule that matches on `-m socket --transparent` and redirects the packets to localhost, but it fails to match SNATed IPv6 packets due to that missing conntrack lookup.

CVSS: 10.0 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 15, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from eb31628e37a0a4e01fffd79dcc7f815d2357f53a before 6488b96a79a26e19100ad872622f04e93b638d7f; from eb31628e37a0a4e01fffd79dcc7f815d2357f53a before 58ab63d3ded2ca6141357a2b24eee8453d0f871d; from eb31628e37a0a4e01fffd79dcc7f815d2357f53a before 1ca2169cc19dca893c7aae6af122852097435d16; from eb31628e37a0a4e01fffd79dcc7f815d2357f53a before 1ec43100f7123010730b7ddfc3d5c2eac19e70e7; from eb31628e37a0a4e01fffd79dcc7f815d2357f53a before 5251041573850e5020cd447374e23010be698898; from eb31628e37a0a4e01fffd79dcc7f815d2357f53a before 2bb139e483f8cbe488d19d8c1135ac3615e2668c; from eb31628e37a0a4e01fffd79dcc7f815d2357f53a before 41904cbb343d115931d6bf79aa2c815cac4ef72b; from eb31628e37a0a4e01fffd79dcc7f815d2357f53a before 221c27259324ec1404f028d4f5a0f2ae7f63ee23; and 1 more ranges	CNA record
linux linux_kernel linux:linux_kernel	from 3.13 before 5.4.292; from 5.5 before 5.10.236; from 5.11 before 5.15.180; from 5.16 before 6.1.133; from 6.2 before 6.6.86; from 6.7 before 6.12.22; from 6.13 before 6.13.10; 6.14	NVD

References

References

https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f	patch
https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d	patch
https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16	patch
https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7	patch
https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898	patch
https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c	patch
https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b	patch
https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23	patch
https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e	patch
https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
1–10 of 11

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.