Out-of-Bound Access in Linux Kernel Affecting Transport Header Processing

CVE-2026-63992

What is CVE-2026-63992?

A vulnerability exists in the Linux kernel's handling of transport headers in the iptunnel_pmtud_check_icmp() function. This flaw may result in out-of-bounds access when the skb transport header is not properly set. Such conditions can lead to security risks as the function attempts to access data based on the IPv4 network header without ensuring that the required ICMP type is present in the skb linear part. The vulnerability has been addressed in recent updates, ensuring improved handling of transport headers.

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