CVE-2026-18727
A flaw was found in open-iscsi's iscsiuio component. This vulnerability involves an integer underflow and out-of-bounds read during Dynamic Host Configuration Protocol for IPv6 (DHCPv6) packet parsing. Specifically, crafted DHCPv6 Advertise traffic with a short User Datagram Protocol (UDP) length can cause the DHCPv6 payload length to underflow. An unauthenticated attacker on an adjacent network segment can exploit this by sending specially crafted IPv6 UDP traffic while the client is in an active DHCPv6 exchange, leading to a denial of service due to a process crash or service disruption.
CSIRTS triage
- What
- An integer underflow in iscsiuio DHCPv6 parsing causes memory corruption and potential code execution.
- Who is affected
- Deployments running open-iscsi with DHCPv6 configuration enabled.
- Urgency
- Medium severity; requires specific DHCPv6 scenario but memory corruption is serious.
- Action
- Update open-iscsi to a patched version when available or disable DHCPv6 if not required.
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Exploitation outlook
- Low exploitation risk0.20% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 10% of all EPSS-scored CVEs.
Advisory coverage (2)
External references
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