Skip to content
Fencer Intel
medium 5.0

CVE-2011-4539 json

dhcpd in ISC DHCP 4.x before 4.2.3-P1 and 4.1-ESV before 4.1-ESV-R4 does not properly handle regular expressions in dhcpd.conf, which allow…

published 2011-12-08 14 y ago modified 2026-06-16 4 mo ago also EUVD-2011-4465

cvss
5.0
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
15.2%
EPSS 15.2% chance of exploitation in 30 days, percentile 96%
public exploits
0
none known

Summary

dhcpd in ISC DHCP 4.x before 4.2.3-P1 and 4.1-ESV before 4.1-ESV-R4 does not properly handle regular expressions in dhcpd.conf, which allows remote attackers to cause a denial of service (daemon crash) via a crafted request packet.

Patch / fix

  • isc-dhcp Debian 13, Debian 12 4.2.2.dfsg.1-5

debian advisories DEBIAN-CVE-2011-4539

  • dhcp RHEL 6 12:4.1.1-25.P1.el6_2.1
  • dhclient RHEL 6 12:4.1.1-25.P1.el6_2.1
  • dhcp-common RHEL 6 12:4.1.1-25.P1.el6_2.1

red hat advisories RHSA-2011:1819

  • dhcp openSUSE Tumbleweed 4.3.3.P1-3.1

opensuse advisories openSUSE-SU-2024:10358-1

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-2011-4539 updated cvss 4.3

dhcp: DoS due to processing certain regular expressions

  • Red Hat Enterprise Linux Desktop (v. 6) dhcp 4.1.1-25.P1.el6_2.1, dhclient 4.1.1-25.P1.el6_2.1, dhcp-common 4.1.1-25.P1.el6_2.1 Red Hat Enterprise Linux Desktop Optional (v. 6) dhcp 4.1.1-25.P1.el6_2.1 Red Hat Enterprise Linux HPC Node (v. 6) dhcp 4.1.1-25.P1.el6_2.1, dhclient 4.1.1-25.P1.el6_2.1, dhcp-common 4.1.1-25.P1.el6_2.1 Red Hat Enterprise Linux HPC Node Optional (v. 6) dhcp 4.1.1-25.P1.el6_2.1 Red Hat Enterprise Linux Server (v. 6) dhcp 4.1.1-25.P1.el6_2.1, dhclient 4.1.1-25.P1.el6_2.1, dhcp-common 4.1.1-25.P1.el6_2.1 Red Hat Enterprise Linux Server Optional (v. 6) dhcp 4.1.1-25.P1.el6_2.1
    +2 more products
    Red Hat Enterprise Linux Workstation (v. 6) dhcp 4.1.1-25.P1.el6_2.1, dhclient 4.1.1-25.P1.el6_2.1, dhcp-common 4.1.1-25.P1.el6_2.1 Red Hat Enterprise Linux Workstation Optional (v. 6) dhcp 4.1.1-25.P1.el6_2.1
    fixed: vendor fix RHSA-2011:1819
  • Red Hat Enterprise Linux 4 dhcp Red Hat Enterprise Linux 5 dhcp
    not affected: vulnerable code not present

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

15.22% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

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.