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Fencer Intel
medium 5.9

CVE-2016-2774 json

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 re…

published 2016-03-09 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-3848

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
73.6%
EPSS 73.6% chance of exploitation in 30 days, percentile 99.4%
public exploits
0
none known

Summary

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.

Patch / fix

  • isc-dhcp Debian 13, Debian 12 4.3.4-1

debian advisories DEBIAN-CVE-2016-2774

  • isc-dhcp Ubuntu 14.04 LTS 4.2.4-7ubuntu12.12
  • isc-dhcp Ubuntu 16.04 LTS 4.3.3-5ubuntu12.9

ubuntu advisories UBUNTU-CVE-2016-2774

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • dhcp RHEL 7 12:4.2.5-47.el7
  • dhclient RHEL 7 12:4.2.5-47.el7
  • dhcp-libs RHEL 7 12:4.2.5-47.el7
  • dhcp-common RHEL 7 12:4.2.5-47.el7

red hat advisories RHSA-2016:2590

  • dhcp SLES for SAP 11 SP4, SLES 11 SP4, SLES 11 SP3-TERADATA +6 more 4.2.4.P2-0.27.1
  • dhcp SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +1 more 4.3.3-9.1
  • dhcp SLES for SAP 12, SLES 12, SLED 12 +1 more 4.2.6-14.6.1
  • dhcp SLES 11 SP2-LTSS 4.2.4.P2-0.11.15.1

suse advisories SUSE-SU-2016:2024-1SUSE-SU-2016:1791-1SUSE-SU-2016:1735-1SUSE-SU-2016:1692-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-2774 updated cvss 2.6

dhcp: unclosed TCP connections to OMAPI or failover ports can cause DoS

  • Red Hat Enterprise Linux 5 dhcp Red Hat Enterprise Linux 6 dhcp, dhclient, dhcp-common
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux Client (v. 7) dhcp 4.2.5-47.el7, dhclient 4.2.5-47.el7, dhcp-libs 4.2.5-47.el7, dhcp-common 4.2.5-47.el7 Red Hat Enterprise Linux Client Optional (v. 7) dhcp 4.2.5-47.el7 Red Hat Enterprise Linux ComputeNode (v. 7) dhcp 4.2.5-47.el7, dhclient 4.2.5-47.el7, dhcp-libs 4.2.5-47.el7, dhcp-common 4.2.5-47.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) dhcp 4.2.5-47.el7 Red Hat Enterprise Linux Server (v. 7) dhcp 4.2.5-47.el7, dhclient 4.2.5-47.el7, dhcp-libs 4.2.5-47.el7, dhcp-common 4.2.5-47.el7 Red Hat Enterprise Linux Server Optional (v. 7) dhcp-devel 4.2.5-47.el7, dhcp-debuginfo 4.2.5-47.el7
    +2 more products
    Red Hat Enterprise Linux Workstation (v. 7) dhcp 4.2.5-47.el7, dhclient 4.2.5-47.el7, dhcp-libs 4.2.5-47.el7, dhcp-common 4.2.5-47.el7 Red Hat Enterprise Linux Workstation Optional (v. 7) dhcp-devel 4.2.5-47.el7, dhcp-debuginfo 4.2.5-47.el7
    fixed: vendor fix RHSA-2016:2590

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

73.62% chance of exploitation in the next 30 days, higher than 99.4% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 7.1 AV:N/AC:M/Au:N/C:N/I:N/A:C

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.