CVE-2026-18726

A flaw was found in open-iscsi. This vulnerability allows a remote attacker on the same local network segment to cause a Denial of Service (DoS) in the iscsiuio daemon. By sending a specially crafted Internet Control Message Protocol version 6 (ICMPv6) Router Advertisement with a zero-length option, the attacker can trigger an infinite loop. This leads to sustained CPU usage, rendering the daemon unresponsive and impacting system availability. A secondary risk of out-of-bounds reads exists with a short IPv6 payload, though no memory corruption or data exposure has been confirmed.

Moderate: This flaw in iscsiuio can lead to a denial of service when processing a specially crafted ICMPv6 Router Advertisement. Exploitation requires an attacker to be on the same Layer 2 network segment as an IPv6-enabled interface handled by iscsiuio, limiting its reachability.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, restrict ICMPv6 Router Advertisements from untrusted sources on any network segment where iscsiuio interfaces are exposed. Alternatively, disable IPv6 Router Advertisement processing on affected interfaces if not operationally required. This may involve configuring firewall rules to filter ICMPv6 type 134 messages or adjusting network interface settings to prevent RA-driven IPv6 configuration. A service restart may be required for changes to take effect.