CVE-2025-22021

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2025-22021
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.

5.5 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16 Patch
https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7 Patch
https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23 Patch
https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c Patch
https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b Patch
https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898 Patch
https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d Patch
https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f Patch
https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e Patch
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:*:*:*:*:*:*:*
History

28 Oct 2025, 20:07

Type Values Removed Values Added
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:*:*:*:*:*:*:*
Summary
  • (es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: netfilter: socket: Lookup orig tuple for IPv6 SNAT nf_sk_lookup_slow_v4 realiza la búsqueda conntrack de paquetes IPv4 para restaurar la 5-tupla original en caso de SNAT, para poder encontrar el socket correcto (si lo hay). Entonces socket_match() puede verificar correctamente si el socket era transparente. Sin embargo, la contraparte IPv6 (nf_sk_lookup_slow_v6) carece de esta búsqueda conntrack, lo que hace que xt_socket no coincida en el socket cuando el paquete fue SNATed. Agregue la misma lógica a nf_sk_lookup_slow_v6. SNAT IPv6 se usa en clústeres de Kubernetes para paquetes pod-to-world, ya que las direcciones de los pods están en la subred fd00::/8 ULA y deben reemplazarse con la dirección externa del nodo. Cilium utiliza Envoy para implementar políticas L7, y Envoy utiliza sockets transparentes. Cilium inserta una regla de preenrutamiento de iptables que coincide con `-m socket --transparent` y redirige los paquetes a localhost, pero no coincide con los paquetes IPv6 SNAT debido a la falta de búsqueda de conntrack.
CWE NVD-CWE-noinfo
First Time Linux linux Kernel
Linux
References () https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16 - () https://git.kernel.org/stable/c/1ca2169cc19dca893c7aae6af122852097435d16 - Patch
References () https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7 - () https://git.kernel.org/stable/c/1ec43100f7123010730b7ddfc3d5c2eac19e70e7 - Patch
References () https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23 - () https://git.kernel.org/stable/c/221c27259324ec1404f028d4f5a0f2ae7f63ee23 - Patch
References () https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c - () https://git.kernel.org/stable/c/2bb139e483f8cbe488d19d8c1135ac3615e2668c - Patch
References () https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b - () https://git.kernel.org/stable/c/41904cbb343d115931d6bf79aa2c815cac4ef72b - Patch
References () https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898 - () https://git.kernel.org/stable/c/5251041573850e5020cd447374e23010be698898 - Patch
References () https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d - () https://git.kernel.org/stable/c/58ab63d3ded2ca6141357a2b24eee8453d0f871d - Patch
References () https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f - () https://git.kernel.org/stable/c/6488b96a79a26e19100ad872622f04e93b638d7f - Patch
References () https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e - () https://git.kernel.org/stable/c/932b32ffd7604fb00b5c57e239a3cc4d901ccf6e - Patch
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.5

16 Apr 2025, 11:15

Type Values Removed Values Added
New CVE
Information

Published : 2025-04-16 11:15

Updated : 2025-10-28 20:07

NVD link : CVE-2025-22021

Mitre link : CVE-2025-22021

CVE.ORG link : CVE-2025-22021

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
NVD-CWE-noinfo