Description
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.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
eb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 6488b96a79a26e19100ad872622f04e93b638d7faffectedeb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 58ab63d3ded2ca6141357a2b24eee8453d0f871daffectedeb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 1ca2169cc19dca893c7aae6af122852097435d16affectedeb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 1ec43100f7123010730b7ddfc3d5c2eac19e70e7affectedeb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 5251041573850e5020cd447374e23010be698898affectedeb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 2bb139e483f8cbe488d19d8c1135ac3615e2668caffectedeb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 41904cbb343d115931d6bf79aa2c815cac4ef72baffectedeb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 221c27259324ec1404f028d4f5a0f2ae7f63ee23affectedeb31628e37a0a4e01fffd79dcc7f815d2357f53a to < 932b32ffd7604fb00b5c57e239a3cc4d901ccf6eaffected
Linux Linux
Default version status: affected
3.13affected0 to < 3.13unaffected5.4.292 to ≤ 5.4.*unaffected5.10.236 to ≤ 5.10.*unaffected5.15.180 to ≤ 5.15.*unaffected6.1.133 to ≤ 6.1.*unaffected6.6.86 to ≤ 6.6.*unaffected6.12.22 to ≤ 6.12.*unaffected6.13.10 to ≤ 6.13.*unaffected6.14.1 to ≤ 6.14.*unaffected6.15 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f ↗
- https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d ↗
- https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16 ↗
- https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7 ↗
- https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898 ↗
- https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c ↗
- https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b ↗
- https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23 ↗
- https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e ↗
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html ↗
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html ↗