CVE-2026-72442: netfilter: flowtable: fix and simplify IP6IP6 tunnel handling
In the Linux kernel, the following vulnerability has been resolved:
netfilter: flowtable: fix and simplify IP6IP6 tunnel handling
Fix nfflowip6tunnelproto() to use pskbmaypull() instead of skbheaderpointer() to ensure the outer IPv6 header is in the skb headroom, which is required for subsequent packet processing. Move ctx->offset update inside the IPPROTOIPV6 conditional block since it should only be adjusted when an IP6IP6 tunnel is actually detected. Simplify the rx path by removing ipv6skipexthdr() 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 encaplimit parameter from nfflowoffloadipv6forward(), nfflowtunnelip6ip6push() and nfflowtunnelv6push(), along with the ipv6teltxoption struct and related headroom/MTU adjustments.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-72442?
The severity of CVE-2026-72442 is rated as risk level 37.
How do I fix CVE-2026-72442?
To fix CVE-2026-72442, update your Linux kernel to the latest version that includes the patch resolving this vulnerability.
What type of system is affected by CVE-2026-72442?
CVE-2026-72442 affects the Linux kernel's netfilter flowtable handling for IP6IP6 tunnels.
What does CVE-2026-72442 specifically address?
CVE-2026-72442 addresses an issue in the nf_flow_ip6_tunnel_proto() function related to proper handling of the outer IPv6 header.
When was CVE-2026-72442 published?
CVE-2026-72442 was published on August 15, 2026.