A flaw was found in open-iscsi. An integer underflow vulnerability in the `iscsiuio` component, specifically during IPv4 Dynamic Host Configuration Protocol (DHCP) parsing, allows a remote attacker on the same local network segment to cause a denial of service. By sending a specially crafted IPv4/UDP DHCP reply, the attacker can trigger an out-of-bounds read, leading to the `iscsiuio` process crashing. This issue affects systems where `iscsiuio` is actively handling IPv4 DHCP traffic.

The version of iscsi-initiator-utils installed on the remote host is prior to 6.2.0.874-7. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3897 advisory.

    open-iscsi: open-iscsi: Stack buffer overflow in idbm record parsing (CVE-2026-18724)

    open-iscsi: open-iscsi: Out-of-bounds access in iscsiuio ICMPv6 echo handling (CVE-2026-18725)

    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. (CVE-2026-18726)

    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. (CVE-2026-18727)

    A flaw was found in open-iscsi. An integer underflow vulnerability in the `iscsiuio` component,     specifically during IPv4 Dynamic Host Configuration Protocol (DHCP) parsing, allows a remote attacker on     the same local network segment to cause a denial of service. By sending a specially crafted IPv4/UDP DHCP     reply, the attacker can trigger an out-of-bounds read, leading to the `iscsiuio` process crashing. This     issue affects systems where `iscsiuio` is actively handling IPv4 DHCP traffic. (CVE-2026-18728)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-2120 advisory.

    open-iscsi: open-iscsi: Stack buffer overflow in idbm record parsing (CVE-2026-18724)

    open-iscsi: open-iscsi: Out-of-bounds access in iscsiuio ICMPv6 echo handling (CVE-2026-18725)

    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. (CVE-2026-18726)

    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. (CVE-2026-18727)

    A flaw was found in open-iscsi. An integer underflow vulnerability in the `iscsiuio` component,     specifically during IPv4 Dynamic Host Configuration Protocol (DHCP) parsing, allows a remote attacker on     the same local network segment to cause a denial of service. By sending a specially crafted IPv4/UDP DHCP     reply, the attacker can trigger an out-of-bounds read, leading to the `iscsiuio` process crashing. This     issue affects systems where `iscsiuio` is actively handling IPv4 DHCP traffic. (CVE-2026-18728)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A flaw was found in open-iscsi. An integer underflow vulnerability in the `iscsiuio` component,     specifically during IPv4 Dynamic Host Configuration Protocol (DHCP) parsing, allows a remote attacker on     the same local network segment to cause a denial of service. By sending a specially crafted IPv4/UDP DHCP     reply, the attacker can trigger an out-of-bounds read, leading to the `iscsiuio` process crashing. This     issue affects systems where `iscsiuio` is actively handling IPv4 DHCP traffic. (CVE-2026-18728)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
341873	Amazon Linux 2 : iscsi-initiator-utils, --advisory ALAS2-2026-3897 (ALAS-2026-3897)	Nessus	Amazon Linux Local Security Checks	Local	medium
341851	Amazon Linux 2023 : iscsi-initiator-utils, iscsi-initiator-utils-devel, iscsi-initiator-utils-iscsiuio (ALAS2023-2026-2120)	Nessus	Amazon Linux Local Security Checks	Local	medium
335023	Linux Distros Unpatched Vulnerability : CVE-2026-18728	Nessus	Misc.	Local	medium

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CVE-2026-18728

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