Description
Stack-based buffer overflow in the script_write_params method in client/dhclient.c in ISC DHCP dhclient 4.1 before 4.1.0p1, 4.0 before 4.0.1p1, 3.1 before 3.1.2p1, 3.0, and 2.0 allows remote DHCP servers to execute arbitrary code via a crafted subnet-mask option.
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 5.0 | dhcp3 | 3.1.1-6+lenny2 | DSA-1833-2, DSA-1833-1 |
| Debian 4.0 | dhcp3 | 3.0.4-13+etch2 | DSA-1833-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 4 | dhcp +2 | 7:3.0.1-65.el4_8.1 | RHSA-2009:1136 |
| RHEL 3 | dhcp +2 | 7:3.0.1-10.2_EL3 | RHSA-2009:1154 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 4.7 EUS | dhcp +2 | 7:3.0.1-62.el4_7.1 | RHSA-2009:1136 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- ISC DHCP dhclient < 3.1.2p1 - Remote Buffer Overflow (PoC) EDB-9265 · dos · Jul 27, 2009 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 4
- RHSA-2009:1136 Red Hat Security Advisory: dhcp security update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2009:1154 Red Hat Security Advisory: dhcp security update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- DSA-1833-1 dhcp3 - arbitrary code execution Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-1833-2 dhcp3 - arbitrary code execution Debian Security (DSA / DLA) · Mar 9, 2026
References
- ADV-2009-1891 vdb-entry
- https://www.isc.org/node/468
- 35830 third-party-advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=507717
- 35832 third-party-advisory
- SSRT100018 vendor-advisory
- 35850 third-party-advisory
- 35785 third-party-advisory
- VU#410676 third-party-advisory
- 35880 third-party-advisory
- SUSE-SA:2009:037 vendor-advisory
- FEDORA-2009-9075 vendor-advisory
- 40551 third-party-advisory
- 55819 vdb-entry
- 35668 vdb-entry
- DSA-1833 vendor-advisory
- GLSA-200907-12 vendor-advisory
- MDVSA-2009:151 vendor-advisory
- RHSA-2009:1136 vendor-advisory
- 35831 third-party-advisory
- 35829 third-party-advisory
- ADV-2010-1796 vdb-entry
- 35841 third-party-advisory
- oval:org.mitre.oval:def:5941 vdb-entry signature
- oval:org.mitre.oval:def:10758 vdb-entry signature
- USN-803-1 vendor-advisory
- NetBSD-SA2009-010 vendor-advisory
- https://www.isc.org/downloadables/12
- RHSA-2009:1154 vendor-advisory
- 37342 third-party-advisory
- 35851 third-party-advisory
- 35849 third-party-advisory
- SSA:2009-195-01 vendor-advisory
- 1022548 vdb-entry
- 36457 third-party-advisory
- FEDORA-2009-8344 vendor-advisory