ghsa-57hq-w56x-2gq6
Vulnerability from github
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": [],
"aliases": [
"CVE-2025-22021"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-16T11:15:42Z",
"severity": null
},
"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\u0027 addresses are in the fd00::/8 ULA subnet and need to be replaced\nwith the node\u0027s 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.",
"id": "GHSA-57hq-w56x-2gq6",
"modified": "2025-04-16T12:31:20Z",
"published": "2025-04-16T12:31:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-22021"
},
{
"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"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.