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CVE-2018-5733
A malicious client can overflow a reference counter in ISC dhcpd
Medium5.9EPSS 20.2%
- Published
- Updated
- Reserved
- Assigned by
- isc
Description
A malicious client which is allowed to send very large amounts of traffic (billions of packets) to a DHCP server can eventually overflow a 32-bit reference counter, potentially causing dhcpd to crash. Affects ISC DHCP 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| iscCNA (assigner) | 3.0 | Medium5.9 | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 20.2% · top 2.5% of all CVEs (4 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.
Weakness
- Successful exploitation of this vulnerability may exhaust the memory available to dhcpd and/or cause it to crash, resulting in a denial of service to clients.
- CWE-190 (opens in a new tab)All about CWE-190 and its CVEs
Affected products
What to do
Solution: Upgrade to the patched release most closely related to your current version of DHCP. DHCP 4.1-ESV-R15-P1 DHCP 4.3.6-P1 DHCP 4.4.1
References (10)
- https://kb.isc.org/docs/aa-01567 (opens in a new tab)x_refsource_CONFIRMx_transferred
- RHSA-2018:0469 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- DSA-4133 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- USN-3586-2 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- RHSA-2018:0483 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- USN-3586-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- 103188 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- 1040437 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- [debian-lts-announce] 20180322 [SECURITY] [DLA 1313-1] isc-dhcp security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- https://security.netapp.com/advisory/ntap-20250425-0010/ (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2018-5733)Record last updated .