Vulnerability in dhcp-server (CVE-2026-18103)
Summary
Vulnerability in dhcp-server (CVE-2026-18103). Risk of unauthorized operations or information disclosure. Exploitable via dhcpd.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-18103 has been found in dhcp-server.
Attackers can target a specific entry point like dhcpd over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.9/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "dhcp-server CVE-2026-18103" on the vendor's site.
CVE-2026-18103 (dhcp-server) — CWE-120 / CVSS v3 4.9
Attack vector: remote (network-reachable) / no user interaction
Attack surface: dhcpd
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-120) exists in dhcp-server. Attackers reach the vulnerable code path via dhcpd.
Check the vendor advisory for the affected versions of dhcp-server. Attack surface: dhcpd.
Severity: Medium (CVSS 4.9/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'dhcp-server' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'dhcp-server' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
dhcp-serverを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-18103 isc-dhcp
- Ubuntu UBUNTU-CVE-2026-18103 isc-dhcp
References
- web nvd.nist.gov
- web secalert@redhat.com
- web secalert@redhat.com
- web github.com