CVE-2026-72442
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk10th percentile - higher than 10% of all known CVEs
Summary
In the Linux kernel, the netfilter flowtable module has a vulnerability related to IP6IP6 tunnel handling. The function nf_flow_ip6_tunnel_proto() uses skb_header_pointer() instead of pskb_may_pull(), which may lead to incorrect packet processing. Additionally, the handling of extension headers was simplified, which may affect correctness.
Risk Assessment
Incorrect packet processing in the fast path may lead to errors in filtering or forwarding traffic, potentially resulting in security bypass or system crash.
Recommendation
Apply a Linux kernel update containing the fix that changes the function to use pskb_may_pull() and simplifies header handling.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: fix and simplify IP6IP6 tunnel handling Fix nf_flow_ip6_tunnel_proto() to use pskb_may_pull() instead of skb_header_pointer() to ensure the outer IPv6 header is in the skb headroom, which is required for subsequent packet processing. Move ctx->offset update inside the IPPROTO_IPV6 conditional block since it should only be adjusted when an IP6IP6 tunnel is actually detected. Simplify the rx path by removing ipv6_skip_exthdr() and checking ip6h->nexthdr directly, as the flowtable fast path only handles simple IP6IP6 encapsulation without extension headers. Drop the tunnel encapsulation limit destination option support from the tx path to match, since the rx path no longer handles extension headers. Remove the encap_limit parameter from nf_flow_offload_ipv6_forward(), nf_flow_tunnel_ip6ip6_push() and nf_flow_tunnel_v6_push(), along with the ipv6_tel_txoption struct and related headroom/MTU adjustments.