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  4. CVE 2026 18727 open iscsi open iscsi integer underflow in
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Back to active CVEs
Medium · CVSS 6.5CVE-2026-18727

Open-iscsi: open-iscsi: integer underflow in iscsiuio dhcpv6 parsingCVE-2026-18727

Answer in brief

CVE-2026-18727 records a Medium severity (CVSS 6.5) vulnerability in Open-iscsi: open-iscsi: integer underflow in iscsiuio dhcpv6 parsing. The current sources do not mark it as known exploited. The current feed maps Red Hat/iscsi-initiator-utils (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 12, 2026Updated Nov 5, 2026Source checked Nov 11, 2026First seen by HOL Aug 12, 2026Material review Nov 5, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 6.5
Exploitation
Not marked as known exploited
Affected software
3 mapped packages or products
Fix availability
Not reported

Why this deserves its current priority

CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Red Hat/iscsi-initiator-utils (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Red Hat/iscsi-initiator-utilsgeneric*Not reported

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Red Hat/iscsi-initiator-utils.
  2. 2Review the reported fix. Source-reported workaround: If DHCPv6 is not required for `iscsiuio`, disable DHCPv6 handling for the relevant network interface. If DHCPv6 is necessary, restrict network exposure to trusted adjacent networks and implement firewall rules to prevent forged DHCPv6 server traffic from reaching clients on shared L2 segments. A system restart or service reload may be required for changes to take effect.

Evidence timeline and material changes

  1. Published upstream

    Aug 12, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Nov 5, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Aug 12, 2026

Sources and claim methodology

  • Source referenceaccess.redhat.com
  • Source referencebugzilla.redhat.com
Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Bluetooth Classic RFCOMM: integer underflow in the MCC TEST command handler leads to out-of-bounds read disclosed to the peer and out-of-bounds writeAlso CWE-191

Record context

Vulnerability class
Missing Auth
EPSS
Not reported
CWE IDs
CWE-191
Source
CVE List V5
Source checked
Nov 11, 2026
References
2 linked sources
Open source record