CVE-2011-1547
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 · uneditedMultiple stack consumption vulnerabilities in the kernel in NetBSD 4.0, 5.0 before 5.0.3, and 5.1 before 5.1.1, when IPsec is enabled, allow remote attackers to cause a denial of service (memory corruption and panic) or possibly have unspecified other impact via a crafted (1) IPv4 or (2) IPv6 packet with nested IPComp headers.
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 · high confidenceStack consumption vulnerability in NetBSD kernel IPsec implementation. When IPsec is enabled, specially crafted IPv4 or IPv6 packets with nested IPComp (IP Compression) headers cause excessive stack usage, leading to memory corruption and kernel panic. Affects NetBSD 4.0, 5.0 before 5.0.3, and 5.1 before 5.1.1.
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= 4.0= 5.0= 5.0.1= 5.0.2= 5.1CVSS 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
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/Au:N/C:P/I:P/A:P
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.
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Check NetBSD versionRun `uname -a` or `sysctl kern.version` to obtain the installed NetBSD versionAffected if The version is 4.0, 5.0, 5.0.1, 5.0.2, or 5.1 (vulnerable versions)
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Confirm IPsec is enabledRun `ipsecctl -s all` or `setkey -D` to query the IPsec configuration and statusAffected if IPsec is actively enabled and processing traffic (vulnerability only triggers when IPsec processes packets)
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Verify IPComp compression is in useCheck IPsec policy files in /etc/ipsec.conf or examine active IPsec SAs using `ipsecctl -sa` for compress (IPComp) entriesAffected if IPComp (protocol 108) is configured or active in any IPsec security association
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Check for nested IPComp packet processingMonitor network traffic or kernel logs for IPComp packets. Use `tcpdump -i any -v ipcomp` to observe IPComp traffic patternsAffected if The system processes IPv4 or IPv6 packets containing nested or multiple IPComp headers (the specific attack vector)
A system is affected if it runs NetBSD 4.0, 5.0, 5.0.1, 5.0.2, or 5.1 with IPsec enabled and is processing IPComp-compressed packets that could contain nested IPComp headers.
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 to NetBSD 5.0.3, 5.1.1, or later versions. If upgrading is not immediately feasible, consider disabling IPsec if not required, or implement network-level filtering to block potentially malicious nested IPComp packets at perimeter defenses.
- Consultation3.0 h
- Implementation6.0 h
- Testing8.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-1547 — 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-2011-1547 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
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- Version or environment caveats, and links to real fixes
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