CVE-2026-58058

Nmap through 7.99 does not keep the IPv6 extension-header walk within the captured packet in ipv6_get_data_primitive (libnetutil/netutil.cc), so the pointer advances past the buffer and the remaining-length computation underflows to a large value. A scanned target or on-path attacker returning a crafted IPv6 response with a truncated extension header can trigger out-of-bounds reads and a crash during raw IPv6 scans.

• nmap 7.99+dfsg-2 (bug https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1140916; unimportant) https://github.com/bikini/exploitarium/tree/main/nmap-ipv6-extlen-wrap-poc https://github.com/nmap/nmap/commit/bb6754e76bb1686315008e1aa1c40202a513fb83 Crash in CLI tool, no security impact