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.
INFO
Published Date :
2025-04-16T10:20:37.695Z
Last Modified :
2025-11-03T19:41:09.284Z
Source :
Linux
AFFECTED PRODUCTS
The following products are affected by CVE-2025-22021 vulnerability.
| Vendors | Products |
|---|---|
| Linux |
|
REFERENCES
Here, you will find a curated list of external links that provide in-depth information to CVE-2025-22021.
