Null Pointer Dereference Vulnerability in Linux Kernel's IPv6 Implementation

CVE-2026-64538

What is CVE-2026-64538?

A vulnerability in the Linux kernel's IPv6 networking stack has been identified, specifically in the fib6_nh_mtu_change() function. This issue arises from a lack of NULL pointer validation when re-fetching the idev structure, which can lead to a dereference of a NULL pointer. Code execution paths that interact with this vulnerability may experience faults, potentially impacting network performance and stability. The problem can occur if addrconf_ifdown() clears the dev->ip6_ptr and the associated routing information is accessed subsequently. The recent patches address this oversight, ensuring safer handling of the idev structure.

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