Linux kernel netfilter do_add_counters race condition

linux-doaddcounters-race-condition (26583) The risk level is classified as MediumMedium Risk


The Linux kernel netfilter module is vulnerable to a race condition in the do_add_counters() function. A local attacker with CAP-NET_ADMIN privileges could exploit this vulnerability to view portions of kernel memory.


Obtain Information


Upgrade to the latest version of Linux kernel ( or later), available from The Linux Kernel Archives Web site. See References.

For Debian GNU/Linux:
Refer to DSA-1097-1 and DSA-1103-1 for patch, upgrade, or suggested workaround information. See References.

For Red Hat Linux 4:
Refer to RHSA-2006:0689-15 for patch, upgrade, or suggested workaround information. See References.

For Turbolinux:
Refer to Red Hat Linux Security Advisory TLSA-2007-2 for patch, upgrade, or suggested workaround information. See References.


  • Gentoo Bugzilla Bug 133465: Kernel: netfilter do_add_counters race (CVE-2006-0039).
  • Red Hat Bugzilla Bug 191698: CVE-2006-0039 netfilter do_add_counters race.
  • The Linux Kernel Archives Web site: ChangeLog-
  • The Linux Kernel Archives Web site: The Linux Kernel Archives.
  • ASA-2006-249: kernel security update (RHSA-2006-0689)
  • BID-18113: Linux Kernel Netfilter Do_Add_Counters Local Race Condition Vulnerability
  • CVE-2006-0039: Race condition in the do_add_counters function in netfilter for Linux kernel 2.6.16 allows local users with CAP_NET_ADMIN capabilities to read kernel memory by triggering the race condition in a way that produces a size value that is inconsistent with allocated memory, which leads to a buffer over-read in IPT_ENTRY_ITERATE.
  • DSA-1097: kernel-source-2.4.27 -- several vulnerabilities
  • DSA-1103: kernel-source-2.6.8 -- several vulnerabilities
  • OSVDB ID: 25697: Linux Kernel Netfilter do_add_counters() Function Local Memory Disclosure
  • RHSA-2006-0689: kernel security update
  • SA20185: Linux Kernel Netfilter Weakness and Two SCTP Vulnerabilities
  • SA21476: Linux Kernel Multiple Vulnerabilities
  • SA22945: Avaya Products Linux Kernel Multiple Vulnerabilities

Platforms Affected:

  • Canonical Ubuntu 5.04
  • Canonical Ubuntu 5.10
  • Canonical Ubuntu 6.06 LTS
  • Debian Debian Linux 3.1
  • Linux Linux Kernel 2.6.16
  • RedHat Enterprise Linux 4 ES
  • RedHat Enterprise Linux 4 Desktop
  • RedHat Enterprise Linux 4 AS
  • RedHat Enterprise Linux 4 WS
  • Turbolinux Turbolinux 8 Server


May 16, 2006

The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall the author/distributor (IBM Internet Security Systems X-Force) be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.

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