CVE-2026-18727

MEDIUM

6.5

CVSS v3

Description

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.

CWE-191

How to fix

Remediation Available

open-iscsiDebian

Fixed in:2.1.13-1CVE-2026-18727

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorAdjacent

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

0.19%probability of exploitation in 30 days

9thpercentile

Low risk: more likely to be exploited than 9% of all known CVEs.

References

Vendor Advisory2

Related Vulnerabilities

Other CWE-191 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0497	Critical	9.8	100%	KEV	Fix
CVE-2020-36228	High	7.5	84%	-	Fix
CVE-2020-36221	High	7.5	84%	-	Fix
CVE-2024-38063	Critical	9.8	71%	-	Fix
CVE-2017-14496	High	7.5	66%	-	Fix
CVE-2004-0184	Medium	5.0	60%	-	Fix

Common questions

How do I fix CVE-2026-18727?

Upgrade open-iscsi on debian unstable to 2.1.13-1 or later.

Is CVE-2026-18727 being actively exploited?

Not that we know of. CVE-2026-18727 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.19% is the estimated probability that it will be exploited in the next 30 days. That is higher than 9% of all scored CVEs.

How severe is CVE-2026-18727?

CVE-2026-18727 has a CVSS v3 base score of 6.5, rated moderate. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-18727 affect?

Published advisories record a fix for open-iscsi (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-25.