A malicious client can overflow a reference counter in ISC dhcpd
Published Jan 16, 2019
7.5
HIGHCVSS 3.1
EPSS 20.24%
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.
Affected products
-
- Version ISC DHCP 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0StatusaffectedConstraints-
- Version
Configuration 1
- ≥ 4.2.0 · ≤ 4.2.8
- ≥ 4.3.0 · ≤ 4.3.6
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1-esv
- 4.1.0
- 4.4.0
Configuration 2
- 6.0
- 7.0
- 6.0
- 7.0
- 7.4
- 7.6
- 7.4
- 7.5
- 7.6
- 6.0
- 7.0
Configuration 3
- 14.04
- 16.04
- 17.10
Configuration 4
- 7.0
- 8.0
- 9.0
No data.
Red Hat Enterprise Linux 6
dhcp-12:4.1.1-53.P1.el6_9.3
Fixed · RHSA-2018:0469
Red Hat Enterprise Linux 7
dhcp-12:4.2.5-58.el7_4.3
Fixed · RHSA-2018:0483
Red Hat Enterprise Linux 5
dhcp
Will not fix
Red Hat Enterprise Linux 8
dhcp
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | dhcp-12:4.1.1-53.P1.el6_9.3 | Fixed | RHSA-2018:0469 |
| Red Hat Enterprise Linux 7 | dhcp-12:4.2.5-58.el7_4.3 | Fixed | RHSA-2018:0483 |
| Red Hat Enterprise Linux 5 | dhcp | Will not fix | n/a |
| Red Hat Enterprise Linux 8 | dhcp | Not affected | n/a |
No package ranges for this CVE.
Remediation
Vendor 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
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
AV:N/AC:L/Au:N/C:N/I:N/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (32 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 20.24% (0.20242) | 97.40th | v5 (v2026.06.15) |
| Jun 15, 2026 | 20.24% (0.20242) | 97.13th | v5 (v2026.06.15) |
| Jun 4, 2026 | 14.48% (0.14479) | 94.57th | v4 (v2025.03.14) |
| May 9, 2026 | 10.26% (0.10256) | 93.22th | v4 (v2025.03.14) |
| Feb 18, 2026 | 11.32% (0.11316) | 93.37th | v4 (v2025.03.14) |
| Nov 21, 2025 | 29.14% (0.29144) | 96.38th | v4 (v2025.03.14) |
| Nov 18, 2025 | 68.60% (0.68597) | 98.65th | v4 (v2025.03.14) |
| Aug 30, 2025 | 29.51% (0.29514) | 96.45th | v4 (v2025.03.14) |
| Jul 13, 2025 | 25.82% (0.25820) | 96.00th | v4 (v2025.03.14) |
| Jun 20, 2025 | 21.20% (0.21198) | 95.35th | v4 (v2025.03.14) |
| Jun 1, 2025 | 17.17% (0.17173) | 94.68th | v4 (v2025.03.14) |
| May 15, 2025 | 33.84% (0.33841) | 96.70th | v4 (v2025.03.14) |
| Apr 15, 2025 | 39.40% (0.39399) | 97.05th | v4 (v2025.03.14) |
| Mar 30, 2025 | 41.11% (0.41106) | 97.11th | v4 (v2025.03.14) |
| Mar 29, 2025 | 32.85% (0.32847) | 95.12th | v4 (v2025.03.14) |
| Mar 17, 2025 | 41.27% (0.41272) | 97.08th | v4 (v2025.03.14) |
| Mar 13, 2025 | 7.92% (0.07921) | 94.41th | v3 (v2023.03.01) |
| Dec 26, 2024 | 9.67% (0.09672) | 94.79th | v3 (v2023.03.01) |
| Oct 31, 2024 | 7.33% (0.07331) | 94.24th | v3 (v2023.03.01) |
| Sep 17, 2024 | 8.62% (0.08618) | 94.61th | v3 (v2023.03.01) |
| Jun 3, 2024 | 6.53% (0.06530) | 93.74th | v3 (v2023.03.01) |
| Apr 25, 2024 | 7.11% (0.07109) | 93.91th | v3 (v2023.03.01) |
| Feb 8, 2024 | 8.70% (0.08701) | 94.30th | v3 (v2023.03.01) |
| Jan 10, 2024 | 16.35% (0.16349) | 95.49th | v3 (v2023.03.01) |
| Mar 7, 2023 | 11.34% (0.11343) | 94.28th | v3 (v2023.03.01) |
| Mar 6, 2023 | 3.36% (0.03358) | 84.40th | v2 (v2022.01.01) |
| Apr 1, 2022 | 3.36% (0.03358) | 82.80th | v2 (v2022.01.01) |
| Feb 4, 2022 | 3.36% (0.03358) | 65.90th | v2 (v2022.01.01) |
| Feb 3, 2022 | 2.07% (0.02069) | 50.36th | v1 |
| Jan 6, 2022 | 2.07% (0.02069) | 49.86th | v1 |
| Sep 1, 2021 | 2.07% (0.02069) | 77.27th | v1 |
| Apr 14, 2021 | 2.07% (0.02069) | 0.00th | v1 |
References (15)
- http://www.securityfocus.com/bid/103188 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- http://www.securitytracker.com/id/1040437 vdb-entryx_refsource_SECTRACKThird Party AdvisoryVDB Entry
- https://access.redhat.com/errata/RHSA-2018:0469 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/errata/RHSA-2018:0483 vendor-advisoryx_refsource_REDHATThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2018-5733 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1549961 Issue Tracking
- https://kb.isc.org/article/AA-01567
- https://kb.isc.org/docs/aa-01567 x_refsource_CONFIRMVendor Advisory
- https://lists.debian.org/debian-lts-announce/2018/03/msg00015.html mailing-listx_refsource_MLISTThird Party Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2018-5733
- https://security.netapp.com/advisory/ntap-20250425-0010/
- https://usn.ubuntu.com/3586-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/3586-2/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2018-5733
- https://www.debian.org/security/2018/dsa-4133 vendor-advisoryx_refsource_DEBIANThird Party Advisory
Change history (0)
No recorded changes yet.