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.

The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:0983 advisory.

    Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

    CVE-2026-18728:
    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-2026-18727:
    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.

    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 ICMPv6     Router Advertisement with a zero-length option, the attacker can trigger an infinite loop, leading to     sustained CPU usage and rendering the daemon unresponsive. A secondary risk of out-of-bounds reads exists     with a short IPv6 payload.

Tenable has extracted the preceding description block directly from the Tencent Linux 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 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'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)

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

ID	Name	Product	Family	Type	Severity
344407	TencentOS Server 4: iscsi-initiator-utils (TSSA-2026:0983)	Nessus	Tencent Local Security Checks	Local	medium
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
335025	Linux Distros Unpatched Vulnerability : CVE-2026-18727	Nessus	Misc.	Local	medium

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CVE-2026-18727

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