CVE-2025-22021 Affecting kernel-debug-modules-core package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.03% (8th percentile)

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  • Snyk IDSNYK-CENTOS9-KERNELDEBUGMODULESCORE-9734259
  • published17 Apr 2025
  • disclosed16 Apr 2025

Introduced: 16 Apr 2025

NewCVE-2025-22021  (opens in a new tab)

How to fix?

There is no fixed version for Centos:9 kernel-debug-modules-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules-core package and not the kernel-debug-modules-core package as distributed by Centos. See How to fix? for Centos:9 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1