{"api_version":"1","generated_at":"2026-08-22T09:16:42+00:00","cve":"CVE-2025-22021","urls":{"html":"https://cve.report/CVE-2025-22021","api":"https://cve.report/api/cve/CVE-2025-22021.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2025-22021","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-22021"},"summary":{"title":"netfilter: socket: Lookup orig tuple for IPv6 SNAT","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2025-04-16 11:15:42","updated_at":"2026-07-30 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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."}],"metrics":[{"cvssV3_1":{"baseScore":10,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-30T05:47:37.698Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f"},{"url":"https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d"},{"url":"https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16"},{"url":"https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7"},{"url":"https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898"},{"url":"https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c"},{"url":"https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b"},{"url":"https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23"},{"url":"https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e"}],"title":"netfilter: socket: Lookup orig tuple for IPv6 SNAT","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2025-22021","datePublished":"2025-04-16T10:20:37.695Z","dateReserved":"2024-12-29T08:45:45.807Z","dateUpdated":"2026-07-30T05:47:37.698Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2025-04-16 11:15:42","lastModifiedDate":"2026-07-30 06:22:03","problem_types":["NVD-CWE-noinfo"],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","baseScore":10,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":6},{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"5.4.292","matchCriteriaId":"7F195470-F0D7-4E43-9F03-A295DFCF6531"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5","versionEndExcluding":"5.10.236","matchCriteriaId":"1DF46FB0-9163-4ABE-8CCA-32A497D4715B"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.11","versionEndExcluding":"5.15.180","matchCriteriaId":"D19801C8-3D18-405D-9989-E6C9B30255FA"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.16","versionEndExcluding":"6.1.133","matchCriteriaId":"F0054446-3F3B-42C4-BDB3-8FDD29D57F23"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.86","matchCriteriaId":"5DB427C2-3400-4B39-AC18-49AECE5221B5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.22","matchCriteriaId":"9F037D3C-D627-4151-8546-1A2E3C2B38A8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.13.10","matchCriteriaId":"E9410CA0-CED8-49BE-9DB4-856654736C32"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.14:*:*:*:*:*:*:*","matchCriteriaId":"82E37853-46C8-4BB6-9FA4-9838FD34D6A2"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2025","CveId":"22021","Ordinal":"1","Title":"netfilter: socket: Lookup orig tuple for IPv6 SNAT","CVE":"CVE-2025-22021","Year":"2025"},"notes":[{"CveYear":"2025","CveId":"22021","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"netfilter: socket: Lookup orig tuple for IPv6 SNAT"}]}}}