Description
ISC DHCP 4.1.x before 4.1-ESV-R13 and 4.2.x and 4.3.x before 4.3.4 does not restrict the number of concurrent TCP sessions, which allows remote attackers to cause a denial of service (INSIST assertion failure or request-processing outage) by establishing many sessions.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 13 | isc-dhcp | 4.3.4-1 | — |
| Debian 12 | isc-dhcp | 4.3.4-1 | — |
| Debian 8 | isc-dhcp | 4.3.1-6+deb8u4 | DLA-2003-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | isc-dhcp | 4.3.3-5ubuntu12.9 | USN-3586-1 |
| Ubuntu 14.04 LTS | isc-dhcp | 4.2.4-7ubuntu12.12 | USN-3586-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | dhcp +4 | 12:4.2.5-47.el7 | RHSA-2016:2590 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | dhcp | 4.3.3-9.1 | SUSE-SU-2016:1791-1 |
| SLES 12 | dhcp | 4.2.6-14.6.1 | SUSE-SU-2016:1692-1 |
| SLES 11 SP4 | dhcp | 4.2.4.P2-0.27.1 | SUSE-SU-2016:2024-1 |
| SLES 11 SP3 | dhcp | 4.2.4.P2-0.27.1 | SUSE-SU-2016:2024-1 |
| SLES 11 SP2 | dhcp | 4.2.4.P2-0.11.15.1 | SUSE-SU-2016:1735-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | dhcp | 4.3.3-9.1 | SUSE-SU-2016:1791-1 |
| SLES for SAP 12 | dhcp | 4.2.6-14.6.1 | SUSE-SU-2016:1692-1 |
| SLES for SAP 11 SP4 | dhcp | 4.2.4.P2-0.27.1 | SUSE-SU-2016:2024-1 |
| SUSE OpenStack Cloud 5 | dhcp | 4.2.4.P2-0.27.1 | SUSE-SU-2016:2024-1 |
| SUSE Manager Proxy 2.1 | dhcp | 4.2.4.P2-0.27.1 | SUSE-SU-2016:2024-1 |
| SUSE Manager 2.1 | dhcp | 4.2.4.P2-0.27.1 | SUSE-SU-2016:2024-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | dhcp | 4.2.4.P2-0.27.1 | SUSE-SU-2016:2024-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | dhcp +4 | 12:4.2.5-47.0.1.el7 | ELSA-2016-2590 |
Advisories 8
- RHSA-2016:2590 Red Hat Security Advisory: dhcp security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-3586-1 isc-dhcp vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-2003-1 isc-dhcp - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:1692-1 Security update for dhcp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1791-1 Security update for dhcp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1735-1 Security update for dhcp SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2024-1 Security update for dhcp SUSE / openSUSE Security Updates · Feb 4, 2026
- ELSA-2016-2590 Moderate: dhcp security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 9, 2016
References
- RHSA-2016:2590 vendor-advisory
- 1035196 vdb-entry
- https://kb.isc.org/article/AA-01354
- http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html
- FEDORA-2016-821f013cb1 vendor-advisory
- USN-3586-1 vendor-advisory
- openSUSE-SU-2016:1843 vendor-advisory
- FEDORA-2016-c93d49faf3 vendor-advisory
- 84208 vdb-entry
- [debian-lts-announce] 20191124 [SECURITY] [DLA 2003-1] isc-dhcp security update mailing-list