Security readout for executives and security teams
Plain-English summary
CVE-2018-5733 can let a malicious DHCP client crash ISC dhcpd by sending extremely large traffic volumes over time. The business impact is service disruption: affected networks may lose automatic IP address assignment until DHCP service is restored. The attack is demanding, but DHCP is often operationally critical.
Executive priority
Treat as a scheduled but important infrastructure fix. It is not marked actively exploited, but DHCP outages can block connectivity and incident response. Patch critical DHCP servers first, especially in high-churn or less trusted network segments.
Technical view
Affected ISC DHCP versions contain a 32-bit reference counter that can overflow after billions of packets from a malicious client, potentially crashing dhcpd. CVSS 3.0 is 5.9 with network attack vector, high complexity, no privileges, no user interaction, and availability-only impact.
Likely exposure
Exposure is most relevant where ISC DHCP servers run affected versions and can receive traffic from untrusted or poorly controlled clients. Internet exposure is not established by the bundle; DHCP is typically network-segment scoped.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. Practical exploitation appears constrained by the requirement for very large packet volumes, but successful abuse can still disrupt DHCP availability.
Researcher notes
Key constraint is the traffic volume needed to overflow the reference counter, matching the high attack complexity score. Research should focus on version confirmation, package backport status, service placement, and whether any appliances embed affected ISC DHCP builds.
Mitigation direction
- Apply ISC or operating-system vendor security updates for affected ISC DHCP packages.
- Prioritize DHCP servers supporting critical user, server, or network-access segments.
- Check Red Hat, Debian, Ubuntu, and other vendor advisories for packaged fixes.
- If no update is confirmed, follow current vendor guidance before relying on compensating controls.
- Limit DHCP traffic to intended client segments where network design allows.
Validation and detection
- Inventory systems running ISC DHCP and record exact dhcpd package versions.
- Compare versions against affected ranges: 4.1.0 through 4.4.0 as listed.
- Verify whether vendor security errata are installed on packaged deployments.
- Confirm DHCP service is not reachable from unintended network segments.
- Avoid high-volume packet testing; validate through versions, advisories, and configuration review.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CVE-2018-5733 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.9 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H2.23.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.9MediumVector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.isc.org/docs/aa-01567CVE reference · x_refsource_CONFIRM
- RHSA-2018:0469CVE reference · vendor-advisory, x_refsource_REDHAT
- DSA-4133CVE reference · vendor-advisory, x_refsource_DEBIAN
- USN-3586-2CVE reference · vendor-advisory, x_refsource_UBUNTU
- RHSA-2018:0483CVE reference · vendor-advisory, x_refsource_REDHAT
- USN-3586-1CVE reference · vendor-advisory, x_refsource_UBUNTU
- [debian-lts-announce] 20180322 [SECURITY] [DLA 1313-1] isc-dhcp security updateCVE reference · mailing-list, x_refsource_MLIST
- https://security.netapp.com/advisory/ntap-20250425-0010/CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.