Is CVE-2026-18727 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-18727 being exploited in the wild.

How severe is CVE-2026-18727?

Medium severity, with a CVSS score of 6.5, published 12 August 2026.

Which products and versions are affected?

open-iscsi iscsi-initiator-utils.

Is there a fix for CVE-2026-18727?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-18727 attacked?

It is attacked from the adjacent network.

Am I affected by CVE-2026-18727?

Check whether you run Open-Iscsi Iscsi-Initiator-Utils. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-18727: open-iscsi integer underflow in DHCPv6 packet parsing

CVE-2026-18727 · Severity: medium · CVSS 6.5 · Published 2026-08-12

A flaw in open-iscsi's DHCPv6 client component can be exploited by an attacker on the same local network to crash the service or disrupt operations. An attacker sends specially crafted IPv6 network traffic while a client is performing network configuration, causing the software to malfunction and become unavailable. This vulnerability only affects systems actively using DHCPv6 for IPv6 network configuration.

Vendors: Open-Iscsi.

Quick answers

Is CVE-2026-18727 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-18727 being exploited in the wild.
How severe is CVE-2026-18727?: Medium severity, with a CVSS score of 6.5, published 12 August 2026.
Which products and versions are affected?: open-iscsi iscsi-initiator-utils.
Is there a fix for CVE-2026-18727?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-18727 attacked?: It is attacked from the adjacent network.
Am I affected by CVE-2026-18727?: Check whether you run Open-Iscsi Iscsi-Initiator-Utils. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is an integer underflow (CWE-191) in the iscsiuio component's DHCPv6 packet parsing logic. Crafted DHCPv6 Advertise messages with abnormally short UDP length fields cause the payload length calculation to underflow, triggering an out-of-bounds read. An unauthenticated attacker on an adjacent network segment (same L2 network) can exploit this by sending malicious IPv6 UDP traffic while the client is actively performing DHCPv6 configuration. Successful exploitation results in a denial of service via process crash or service disruption. No remote code execution or data breach is possible; the impact is limited to availability. Patches are expected from the vendor but fix availability is not yet specified in this advisory.

Affected products

open-iscsi iscsi-initiator-utils

Timeline

2026-08-12: disclosed

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.