CVE-2026-18726

Daemon hang via zero-length ICMPv6 option

Published Aug 12, 2026 · Updated Aug 12, 2026

Denial of service in iscsiuio on Red Hat Enterprise Linux 9 and 10 allows remote attackers to hang it with a crafted ICMPv6 Router Advertisement. The Router Advertisement option parser fails to advance past an option whose length field is zero, leaving its processing loop on the same input. Exploitation requires Layer 2 access to an IPv6-enabled interface handled by iscsiuio and causes sustained CPU use and daemon unresponsiveness; the reported short-payload read has no confirmed disclosure or corruption.

CVSS severity6.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in iscsiuio on Red Hat Enterprise Linux 9 and 10 allows remote attackers to hang it with a crafted ICMPv6 Router Advertisement. The Router Advertisement option parser fails to advance past an option whose length field is zero, leaving its processing loop on the same input. Exploitation requires Layer 2 access to an IPv6-enabled interface handled by iscsiuio and causes sustained CPU use and daemon unresponsiveness; the reported short-payload read has no confirmed disclosure or corruption.

The record

CVE
CVE-2026-18726
Published
Aug 12, 2026
Updated
Aug 12, 2026
Vendor
389 Directory Server
Product
Red Hat Enterprise Linux 10
Classifications
CWE-835, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

Published CVSS scores

6.5Red HatCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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