Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV L L L N U N N H 5.5 .0043 36.0 —
AFFECTED Product Versions Fixed Linux eb31628e37a0a4e01fffd79dcc7f815d2357f53a – — Linux 3.13 – 5.4.292
TIMELINE Dec 29 Reserved by Linux Apr 16 Published (CNA: Linux) Jul 30 RESCORED — CVE-2025-22021 (Linux). CVSS 10 → 5.5 (NVD).
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.
| Date | Event | Detail |
|---|---|---|
| December 29, 2024 | Reserved | Reserved by Linux |
| April 16, 2025 | Published | Published (CNA: Linux) |
| July 30, 2026 | RESCORED | RESCORED — CVE-2025-22021 (Linux). CVSS 10 → 5.5 (NVD). |
Authoritative record: CVE-2025-22021 at cve.org
Vendors: linux
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-22021 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.