Description
The snmp_trap_decode function in the SNMP NAT helper for Linux kernel before 2.6.16.18 allows remote attackers to cause a denial of service (crash) via unspecified remote attack vectors that cause failures in snmp_trap_decode that trigger (1) frees of random memory or (2) frees of previously-freed memory (double-free) by snmp_trap_decode as well as its calling function, as demonstrated via certain test cases of the PROTOS SNMP test suite.
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 3.1 | fai-kernels | 1.9.1sarge4 | DSA-1184-2, DSA-1183-1 |
| Debian 3.1 | kernel-source-2.4.27 | 2.4.27-10sarge4 | DSA-1183-1 |
| Debian 3.1 | kernel-source-2.6.8 | 2.6.8-16sarge5 | DSA-1184-2 |
| Debian 3.1 | systemimager | 3.2.3-6sarge3 | DSA-1183-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 4 | kernel +8 | 2.6.9-42.0.2.EL | RHSA-2006:0617 |
| RHEL 3 | kernel +8 | 2.4.21-47.EL | RHSA-2006:0437 |
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.
Exploit-DB 1
- Linux Kernel < 2.6.16.18 - Netfilter NAT SNMP Module Remote Denial of Service EDB-1880 · dos · Jun 5, 2006 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 4
- RHSA-2006:0617 Red Hat Security Advisory: kernel security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2006:0437 Red Hat Security Advisory: Updated kernel packages for Red Hat Enterprise Linux 3 Update 8 Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-1183-1 kernel-source-2.4.27 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-1184-2 kernel-source-2.6.8 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
References
- RHSA-2006:0437 vendor-advisory
- SUSE-SA:2006:042 vendor-advisory
- 1016153 vdb-entry
- RHSA-2006:0617 vendor-advisory
- 20716 third-party-advisory
- 21605 third-party-advisory
- SUSE-SA:2006:047 vendor-advisory
- 25750 vdb-entry
- 21136 third-party-advisory
- DSA-1183 vendor-advisory
- 20182 third-party-advisory
- USN-302-1 vendor-advisory
- ADV-2006-1916 vdb-entry
- 22082 third-party-advisory
- 21983 third-party-advisory
- SUSE-SA:2006:064 vendor-advisory
- 21035 third-party-advisory
- 22174 third-party-advisory
- http://kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.18
- oval:org.mitre.oval:def:11318 vdb-entry signature
- RHSA-2006:0580 vendor-advisory
- http://support.avaya.com/elmodocs2/security/ASA-2006-180.htm
- 22822 third-party-advisory
- 20225 third-party-advisory
- 18081 vdb-entry
- linux-snmp-nathelper-dos(26594) vdb-entry
- 21498 third-party-advisory
- http://support.avaya.com/elmodocs2/security/ASA-2006-203.htm
- VU#681569 third-party-advisory
- http://www.kernel.org/git/?p=linux/kernel/git/stable/linux-2.6.16.y.git%3Ba=commit%3Bh=1db6b5a66e93ff125ab871d6b3f7363412cc87e8
- 22093 third-party-advisory
- MDKSA-2006:087 vendor-advisory
- DSA-1184 vendor-advisory
- 21179 third-party-advisory