CVE-2026-18727

Name	CVE-2026-18727
Description	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1144935

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
open-iscsi (PTS)	bookworm	2.1.8-1	vulnerable
	trixie	2.1.11-1+deb13u2	vulnerable
	forky, sid	2.1.12-2	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
open-iscsi	source	(unstable)	(unfixed)			1144935

Notes

[trixie] - open-iscsi <no-dsa> (Minor issue)
https://bugzilla.redhat.com/show_bug.cgi?id=2462956
https://github.com/open-iscsi/open-iscsi/issues/543
https://github.com/open-iscsi/open-iscsi/pull/544
Fixed by: https://github.com/open-iscsi/open-iscsi/commit/0bdc1ab6718215e67a4acff1e711fc8c6693cff4