The radvdump utility in radvd-project versions before 2.21 contains a stack-based buffer overflow (CWE-121) in its Route Information option parser. Specifically, the function print_ff() copies up to 2032 bytes from attacker-controlled ICMPv6 Router Advertisement packet data into a fixed 16-byte struct in6_addr buffer on the stack, causing an overflow by up to 2016 bytes. This vulnerability does not affect the main radvd daemon. The issue is patched in radvdump version 2.21.

Successful exploitation of this vulnerability could allow an attacker to overwrite stack memory in the radvdump utility, potentially leading to arbitrary code execution or denial of service. However, the vulnerability requires processing a crafted ICMPv6 Router Advertisement and has a high attack complexity and privileges required, with no user interaction needed. The main radvd daemon is not vulnerable, limiting the scope of impact to the radvdump utility only.

Upgrade radvdump to version 2.21 or later, where this stack-based buffer overflow vulnerability is patched. Since no official patch links or advisories are provided, verify the version before use. Avoid using vulnerable versions of radvdump to process untrusted ICMPv6 Router Advertisements. Patch status is not explicitly confirmed beyond the version 2.21 fix; check vendor advisories for the latest remediation guidance.