Linux Kernel Buffer Overflow Vulnerability in ERSPAN Handling by Vendor

CVE-2025-71128

What is CVE-2025-71128?

A vulnerability exists in the Linux kernel related to the handling of ERSPAN traffic in GRE tunnels. The struct ip_tunnel_info contains a flexible array member, options, which relies on the options_len counter for runtime bounds checking. Failure to properly initialize options_len before referencing options can lead to a buffer overflow. This issue manifests when the kernel is compiled with GCC 15+ and FORTIFY_SOURCE configured, potentially causing a kernel panic. Users are recommended to ensure that the proper helper function ip_tunnel_info_opts_set() is utilized to avoid fragmented updates that can compromise system stability.

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