CVE-2026-18103Network attack vector

Persistent service crash via OMAPI lease overflow

Published Aug 4, 2026 · Updated Aug 4, 2026

Buffer overflow in dhcp-server on Red Hat Enterprise Linux 6, 7, 8, and 9 allows remote attackers to crash dhcpd through OMAPI. The print_hw_addr() function writes an oversized InfiniBand hardware address from a crafted lease creation request beyond its buffer. Reachability requires network access to the configured OMAPI port; absent TSIG authentication, no credentials are required, and the resulting lease entry blocks automatic restart.

CVSS severity4.9
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in dhcp-server on Red Hat Enterprise Linux 6, 7, 8, and 9 allows remote attackers to crash dhcpd through OMAPI. The print_hw_addr() function writes an oversized InfiniBand hardware address from a crafted lease creation request beyond its buffer. Reachability requires network access to the configured OMAPI port; absent TSIG authentication, no credentials are required, and the resulting lease entry blocks automatic restart.

The record

CVE
CVE-2026-18103
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
389 Directory Server
Product
Red Hat Enterprise Linux 6
Classifications
CWE-120, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat Enterprise Linux 6Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

Published CVSS scores

4.9Red HatCVSS:3.1/AV:N/AC:L/PR:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499Endpoint Denial of Service

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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