Linux KernelOperating system · Linux
CVE-2005-3809
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe nfattr_to_tcp function in ip_conntrack_proto_tcp.c in ctnetlink in Linux kernel 2.6.14 up to 2.6.14.3 allows attackers to cause a denial of service (kernel oops) via an update message without private protocol information, which triggers a null dereference.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA null pointer dereference vulnerability exists in the nfattr_to_tcp function in ip_conntrack_proto_tcp.c within ctnetlink in Linux kernel 2.6.14 through 2.6.14.3. When processing an update message that lacks private protocol information, the function attempts to dereference a null pointer, triggering a kernel oops and resulting in a denial of service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
= 2.6.14= 2.6.14.1= 2.6.14.2= 2.6.14.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:L/Au:N/C:N/I:N/A:C
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Check the running kernel versionRun 'uname -r' or 'cat /proc/version' to obtain the exact kernel version stringAffected if The version is exactly 2.6.14, 2.6.14.1, 2.6.14.2, or 2.6.14.3
-
Verify ip_conntrack module availabilityRun 'lsmod | grep ip_conntrack' or check /proc/net/ip_conntrack to see if the connection tracking module is loadedAffected if The ip_conntrack or nf_conntrack module is loaded and in use
-
Check if ctnetlink is activeRun 'cat /proc/net/netfilter/nf_conntrack' or use 'conntrack -L' if the conntrack-tools package is installedAffected if The system is actively tracking connections via netfilter ctnetlink interface
-
Confirm netfilter support is compiled inCheck /boot/config-$(uname -r) for CONFIG_IP_NF_CONNTRACK or CONFIG_NF_CONNTRACK settings, or check /sys/module/ for netfilter modulesAffected if Netfilter connection tracking is enabled in the kernel configuration
The environment is affected only if the kernel version matches exactly 2.6.14 through 2.6.14.3 AND the ip_conntrack/netfilter connection tracking subsystem is actively loaded or compiled in.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade the Linux kernel to a version beyond 2.6.14.3 that contains the patched nfattr_to_tcp function with proper null pointer handling, or apply the upstream kernel patch to the affected version.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,720.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2005-3809 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2005-3809 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data