CVE-2026-18728
Received Received - Intake

Integer Underflow in Open-iSCSI iscsiuio DHCP Parsing

Publication date: 2026-08-13

Last updated on: 2026-08-13

Assigner: Red Hat, Inc.

Description
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.

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Meta Information

Published
2026-08-13
Last Modified
2026-08-13
Generated
2026-08-13
AI Q&A
2026-08-13
EPSS Evaluated
N/A
NVD
CVE-2026-18728
EUVD
EUVD-2026-57715

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
red_hat open-iscsi 6.2.1.11

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-191 The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

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Executive Summary

This is an integer underflow vulnerability in the open-iscsi package, specifically in the iscsiuio component that handles IPv4 DHCP traffic. It occurs when processing malformed IPv4/UDP DHCP replies, causing an out-of-bounds read that crashes the iscsiuio process. Exploitation requires a remote attacker on the same local network segment to send a specially crafted DHCP reply.

Detection Guidance

To detect this vulnerability, check if the iscsiuio component is running and configured for IPv4 DHCP on affected systems. Monitor for crashes in the iscsiuio process, which may indicate exploitation. Use network traffic analysis tools like tcpdump to inspect DHCP traffic for malformed IPv4/UDP packets targeting the local network segment.

Impact Analysis

This vulnerability can cause a denial of service by crashing the iscsiuio process, which manages iSCSI network traffic. Systems using IPv4 DHCP with iscsiuio are affected. The impact is limited to process crashes without code execution or privilege escalation.

Compliance Impact

This vulnerability primarily causes a denial of service by crashing the iscsiuio process, which may disrupt network services but does not directly lead to data breaches or unauthorized access. Compliance impacts would be indirect, such as potential service unavailability affecting data processing or access, which could violate availability requirements in GDPR or HIPAA. However, the vulnerability does not inherently violate these standards as it does not expose or alter sensitive data.

Mitigation Strategies

Disable IPv4 DHCP on interfaces managed by iscsiuio by reconfiguring to static IP addresses. Restrict network access to these interfaces using firewall rules to limit DHCP/BOOTP traffic to trusted infrastructure. Alternatively, block untrusted systems from the local broadcast domain to prevent crafted DHCP replies from reaching the vulnerable component.

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