CVE-2025-22021
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.5% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.5% in the next 30 days (EPSS).
- Severity: 10.0 CRITICAL (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.5% · EPSS, next 30 days
- Record status
- Modified
Affected
- Linux Kernel < 5.4.292
- Linux Kernel < 5.10.236
- Linux Kernel < 5.15.180
- Linux Kernel < 6.1.133
- Linux Kernel < 6.6.86
- Linux Kernel < 6.12.22
- Linux Kernel < 6.13.10
- Linux Kernel 6.14
Attack profile CVSS 3.1 · 10.0
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-22021.md and follow it. Check whether this project is affected by CVE-2025-22021. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16
- https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7
- https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23
- https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c
- https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b
- https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898
- https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d
- https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f
- https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e
References
- https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16
- https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7
- https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23
- https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c
- https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b
- https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898
- https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d
- https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f
- https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html