IPv6 Fragmentation Vulnerability in RIOT Operating System by RIOT OS

CVE-2025-66647

What is CVE-2025-66647?

A vulnerability has been identified in the IPv6 fragmentation reassembly implementation of RIOT OS v2025.07. The issue arises due to a lack of size checks when copying the contents of the first fragment into the reassembly buffer, allowing an attacker to create a small reassembly buffer. An attacker can exploit this flaw by sending a shorter fragment with offset=0, potentially resulting in buffer overflow and subsequent memory corruption. This vulnerability could lead to further exploitation avenues, such as remote code execution, making it essential for users employing the gnrc_ipv6_ext_frag module to upgrade to version 2025.10, which addresses this issue.

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