A flaw in the ICMPv6 option validation routine allows an attacker to craft a packet with a length residue that is not properly checked, resulting in improper bounds checking (CWE-125), over‑reading adjacent memory (CWE-1287), integer overflow (CWE-191), and an endless loop condition (CWE-835). This can cause an infinite loop or a harmless over‑read that propagates bogus data into the neighbor cache and ultimately blocks the highest‑priority IP thread. The result is a system halt that only recovers after a watchdog reset, effectively denying service to all users while the affected process is blocked.

The vulnerability appears in Eclipse Foundation’s NetX Duo network stack. All firmware builds that incorporate the _nx_icmpv6_validate_options function without the later correction are potentially impacted; no specific version list is supplied, so any unpatched release should be considered at risk.

The CVSS score of 7.1 indicates a significant risk, and the EPSS score is not available, although the lack of a KEV listing suggests no active exploitation campaigns have been reported yet. The exploit requires only the ability to send crafted ICMPv6 packets to the device, a capability that is network‑reachable and does not require local privilege. An attacker could trigger a denial of service by sending packets that cause the IP thread to loop indefinitely or read past the packet boundary, leading to an unresponsive system until a watchdog reset occurs.