ALAS2023-2026-2120

References: CVE-2026-18724  CVE-2026-18725  CVE-2026-18726  CVE-2026-18727  CVE-2026-18728 
FAQs regarding Amazon Linux ALAS/CVE Severity

Issue Overview:

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)

Issue Correction:
Run dnf update iscsi-initiator-utils --releasever 2023.12.20260831 or dnf update --advisory ALAS2023-2026-2120 --releasever 2023.12.20260831 to update your system.
More information on how to update your system can be found on this page: Amazon Linux 2023 documentation

New Packages:

aarch64:
    python3-iscsi-initiator-utils-debuginfo-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.aarch64
    iscsi-initiator-utils-debuginfo-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.aarch64
    python3-iscsi-initiator-utils-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.aarch64
    iscsi-initiator-utils-iscsiuio-debuginfo-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.aarch64
    iscsi-initiator-utils-devel-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.aarch64
    iscsi-initiator-utils-debugsource-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.aarch64
    iscsi-initiator-utils-iscsiuio-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.aarch64
    iscsi-initiator-utils-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.aarch64

src:
    iscsi-initiator-utils-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.src

x86_64:
    iscsi-initiator-utils-debuginfo-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.x86_64
    iscsi-initiator-utils-iscsiuio-debuginfo-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.x86_64
    python3-iscsi-initiator-utils-debuginfo-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.x86_64
    iscsi-initiator-utils-iscsiuio-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.x86_64
    python3-iscsi-initiator-utils-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.x86_64
    iscsi-initiator-utils-devel-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.x86_64
    iscsi-initiator-utils-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.x86_64
    iscsi-initiator-utils-debugsource-6.2.1.4-10.git2a8f9d8.amzn2023.0.4.x86_64