CVE-2026-18103 (GCVE-0-2026-18103)

Vulnerability from cvelistv5 – Published: 2026-08-04 23:08 – Updated: 2026-11-10 20:35
VLAI
Title
Dhcp-server: dhcp-server: persistent denial of service due to buffer overflow via omapi
Summary
A flaw was found in dhcp-server. A remote attacker with network access to the OMAPI (Open Management Application Programming Interface) port, especially if not secured with TSIG (Transaction Signature) key authentication, could send a specially crafted lease creation request. This request, containing an overly long InfiniBand MAC address, triggers a buffer overflow in the `print_hw_addr()` function. Successful exploitation leads to a persistent denial of service (DoS), causing the `dhcpd` service to crash and preventing it from restarting without manual intervention.
Severity
4.9 (Medium)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-05 13:58 UTC
CWE
  • CWE-120 - Buffer Copy without Checking Size of Input
Assigner
redhat CNA under the redhat root
CNA scorecard B 82/100 over 1212 records in the last 180 days details
References
URL Tags
https://access.redhat.com/errata/RHSA-2026:97486 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-18103 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2508081 issue-trackingx_refsource_REDHAT
Impacted products
Vendor Product Version CPE status
Red Hat Red Hat Enterprise Linux 9 Unaffected: 12:4.4.2-22.b1.el9 , < * (rpm)
    cpe:/o:redhat:enterprise_linux:9::baseos
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 6     cpe:/o:redhat:rhel_els:6
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 7     cpe:/o:redhat:rhel_els:7
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 8     cpe:/a:redhat:enterprise_linux:8
Create a notification for this product.
Date Public
2026-07-28 17:35
Credits
This issue was discovered by Martin Osvald (Red Hat).
Show details on NVD website
To clipboard 

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Workarounds

CNA · redhat
To mitigate this issue, secure OMAPI access by configuring TSIG key authentication to prevent unauthorized connections to the OMAPI port (7911). If the `dhcpd` service has already crashed due to this flaw, manually remove the problematic InfiniBand lease entry from `/var/lib/dhcpd/dhcpd.leases` and then restart the `dhcpd` service. Restarting the `dhcpd` service may temporarily interrupt DHCP services for clients.

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Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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    Related by attack behaviour

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