iptables nftables

The iptables nftables tag covers a Linux kernel security issue involving SYNPROXY in the netfilter subsystem. The reported CVE-2026-53269 affects specific upstream kernel ranges where concurrent iptables and nftables SYNPROXY configuration can race during hook registration and shared reference-count management. The issue is rated medium severity, with potential impact on system availability, and applies to Linux systems, custom images, appliances, or firmware builds using netfilter SYNPROXY. Tagged guidance focuses on identifying affected kernel lines, confirming whether SYNPROXY is enabled or configured, and reviewing remediation requirements for systems that may be exposed to this condition.