CVE-2026-18103
Dhcp-server: dhcp-server: persistent denial of service due to buffer overflow via omapi
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Dhcp-server: dhcp-server: persistent denial of service due to buffer overflow via omapi
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.
- Record
CVE-2026-18103- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-120
- Updated
- 2026-11-06
EUVDEUVD-2026-52999
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.
- Record
EUVD-2026-52999- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-06
GitHub AdvisoriesGHSA-wq4j-5vp3-jcrx
A flaw was found in dhcp-server. A remote attacker with network access to the OMAPI (Open...
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.
- Record
GHSA-wq4j-5vp3-jcrx- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-120
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-18103- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-120
- Updated
- 2026-11-06
OSVDEBIAN-CVE-2026-18103
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.
- Record
DEBIAN-CVE-2026-18103- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-07
OSVUBUNTU-CVE-2026-18103
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.
- Record
UBUNTU-CVE-2026-18103- CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
isc-dhcpDebian:12 |
All versions, plus listed versions 4.4.3-P1-24.4.3-P1-34.4.3-P1-44.4.3-P1-54.4.3-P1-5~exp1 Show 4 moreShow less4.4.3-P1-5~exp24.4.3-P1-64.4.3-P1-74.4.3-P1-8 |
None known |
isc-dhcpDebian:13 |
All versions, plus listed versions 4.4.3-P1-8 |
None known |
isc-dhcpUbuntu:Pro:14.04:LTS |
All versions, plus listed versions 4.2.4-7ubuntu84.2.4-7ubuntu94.2.4-7ubuntu104.2.4-7ubuntu114.2.4-7ubuntu12 Show 14 moreShow less4.2.4-7ubuntu12.14.2.4-7ubuntu12.24.2.4-7ubuntu12.34.2.4-7ubuntu12.44.2.4-7ubuntu12.54.2.4-7ubuntu12.64.2.4-7ubuntu12.74.2.4-7ubuntu12.84.2.4-7ubuntu12.94.2.4-7ubuntu12.104.2.4-7ubuntu12.124.2.4-7ubuntu12.134.2.4-7ubuntu12.13+esm14.2.4-7ubuntu12.13+esm2 |
None known |
isc-dhcpUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 4.3.1-5ubuntu34.3.1-5ubuntu44.3.1-5ubuntu54.3.3-5ubuntu14.3.3-5ubuntu2 Show 17 moreShow less4.3.3-5ubuntu44.3.3-5ubuntu54.3.3-5ubuntu74.3.3-5ubuntu84.3.3-5ubuntu94.3.3-5ubuntu104.3.3-5ubuntu114.3.3-5ubuntu124.3.3-5ubuntu12.14.3.3-5ubuntu12.34.3.3-5ubuntu12.44.3.3-5ubuntu12.64.3.3-5ubuntu12.74.3.3-5ubuntu12.94.3.3-5ubuntu12.104.3.3-5ubuntu12.10+esm14.3.3-5ubuntu12.10+esm2 |
None known |
isc-dhcpUbuntu:18.04:LTS |
All versions, plus listed versions 4.3.5-3ubuntu24.3.5-3ubuntu34.3.5-3ubuntu44.3.5-3ubuntu54.3.5-3ubuntu6 Show 5 moreShow less4.3.5-3ubuntu74.3.5-3ubuntu7.14.3.5-3ubuntu7.24.3.5-3ubuntu7.34.3.5-3ubuntu7.4 |
None known |
isc-dhcpUbuntu:20.04:LTS |
All versions, plus listed versions 4.4.1-2ubuntu54.4.1-2ubuntu64.4.1-2.1ubuntu14.4.1-2.1ubuntu24.4.1-2.1ubuntu3 Show 7 moreShow less4.4.1-2.1ubuntu44.4.1-2.1ubuntu54.4.1-2.1ubuntu5.20.04.14.4.1-2.1ubuntu5.20.04.24.4.1-2.1ubuntu5.20.04.34.4.1-2.1ubuntu5.20.04.44.4.1-2.1ubuntu5.20.04.5 |
None known |
isc-dhcpUbuntu:22.04:LTS |
All versions, plus listed versions 4.4.1-2.3ubuntu14.4.1-2.3ubuntu24.4.1-2.3ubuntu2.14.4.1-2.3ubuntu2.24.4.1-2.3ubuntu2.34.4.1-2.3ubuntu2.4 |
None known |
isc-dhcpUbuntu:24.04:LTS |
All versions, plus listed versions 4.4.3-P1-2ubuntu54.4.3-P1-4ubuntu14.4.3-P1-4ubuntu2 |
None known |
isc-dhcpUbuntu:26.04:LTS |
All versions, plus listed versions 4.4.3-P1-4ubuntu2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | EUVD | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-18103 is a medium vulnerability (CVSS 4.9) in Red Hat Enterprise Linux 6, published August 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.71%, the 53rd percentile. No source names a fixed version.