netfilter: socket: Lookup orig tuple for IPv6 SNAT
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 3.13 and later | 5.4.292, 5.10.236, 5.15.180, 6.1.133, 6.6.86, 6.12.22, 6.13.10, 6.14.1, 6.15 | Patch available | CNA |
- Linux VendorLinux Affected 3.13 and later Fixed in 5.4.292, 5.10.236, 5.15.180, 6.1.133, 6.6.86, 6.12.22, 6.13.10, 6.14.1, 6.15 Patch available CNA
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 3.13 to before 5.4.292; 5.5 to before 5.10.236; 5.11 to before 5.15.180; 5.16 to before 6.1.133; 6.2 to before 6.6.86; 6.7 to before 6.12.22; 6.13 to before 6.13.10 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.14:*:*:*:*:*:*:* | 6.14 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.13 to before 5.4.292; 5.5 to before 5.10.236; 5.11 to before 5.15.180; 5.16 to before 6.1.133; 6.2 to before 6.6.86; 6.7 to before 6.12.22; 6.13 to before 6.13.10 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.14:*:*:*:*:*:*:* Versions 6.14 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.4.292, 5.10.236, 5.15.180, 6.1.133, 6.6.86, 6.12.22, 6.13.10, 6.14.1, 6.15
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2025-22021
- 2026-10-03 Alias added: GHSA-57hq-w56x-2gq6
- 2026-10-16 CISA SSVC decision points changed
References
Patch 9
- https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f
- https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d
- https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16
- https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7
- https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898
- https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c
- https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b
- https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23
- https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2025-22021 · CVE Program
- CVE-2025-22021 · NVD
- FIRST EPSS
- GHSA-57hq-w56x-2gq6 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-22021 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences