{"id":"CVE-2025-22021","summary":"netfilter: socket: Lookup orig tuple for IPv6 SNAT","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: socket: Lookup orig tuple for IPv6 SNAT\n\nnf_sk_lookup_slow_v4 does the conntrack lookup for IPv4 packets to\nrestore the original 5-tuple in case of SNAT, to be able to find the\nright socket (if any). Then socket_match() can correctly check whether\nthe socket was transparent.\n\nHowever, the IPv6 counterpart (nf_sk_lookup_slow_v6) lacks this\nconntrack lookup, making xt_socket fail to match on the socket when the\npacket was SNATed. Add the same logic to nf_sk_lookup_slow_v6.\n\nIPv6 SNAT is used in Kubernetes clusters for pod-to-world packets, as\npods' addresses are in the fd00::/8 ULA subnet and need to be replaced\nwith the node's external address. Cilium leverages Envoy to enforce L7\npolicies, and Envoy uses transparent sockets. Cilium inserts an iptables\nprerouting rule that matches on `-m socket --transparent` and redirects\nthe packets to localhost, but it fails to match SNATed IPv6 packets due\nto that missing conntrack lookup.","modified":"2026-04-16T04:38:35.246290440Z","published":"2025-04-16T10:20:37.695Z","related":["SUSE-SU-2025:01919-1","SUSE-SU-2025:01951-1","SUSE-SU-2025:01964-1","SUSE-SU-2025:01965-1","SUSE-SU-2025:01967-1","SUSE-SU-2025:01972-1","SUSE-SU-2025:01983-1","SUSE-SU-2025:02000-1","SUSE-SU-2025:20408-1","SUSE-SU-2025:20413-1","SUSE-SU-2025:20419-1","SUSE-SU-2025:20421-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/22xxx/CVE-2025-22021.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898"},{"type":"WEB","url":"https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/22xxx/CVE-2025-22021.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-22021"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"eb31628e37a0a4e01fffd79dcc7f815d2357f53a"},{"fixed":"6488b96a79a26e19100ad872622f04e93b638d7f"},{"fixed":"58ab63d3ded2ca6141357a2b24eee8453d0f871d"},{"fixed":"1ca2169cc19dca893c7aae6af122852097435d16"},{"fixed":"1ec43100f7123010730b7ddfc3d5c2eac19e70e7"},{"fixed":"5251041573850e5020cd447374e23010be698898"},{"fixed":"2bb139e483f8cbe488d19d8c1135ac3615e2668c"},{"fixed":"41904cbb343d115931d6bf79aa2c815cac4ef72b"},{"fixed":"221c27259324ec1404f028d4f5a0f2ae7f63ee23"},{"fixed":"932b32ffd7604fb00b5c57e239a3cc4d901ccf6e"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-22021.json"}}],"schema_version":"1.7.5"}