Segmentation Fault in Linux Kernel's IPv6 Decapsulation Mechanism

CVE-2026-80840

What is CVE-2026-80840?

A buffer overflow vulnerability exists in the Linux kernel due to improper handling of IPv6 control blocks during IPIP decapsulation. When an IPv4 packet is encapsulated within IPv6 segments, the inner packet can unintentionally utilize stale data from the outer IPv6 packet. This flaw allows an attacker to manipulate the source of the options length, resulting in a potential buffer overflow condition. The vulnerability may lead to unexpected behaviors, such as system crashes or unauthorized access, if exploited. Developers are encouraged to apply updates to mitigate this issue.

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