CVE-1999-0903
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 · uneditedgenfilt in the AIX Packet Filtering Module does not properly filter traffic to destination ports greater than 32767.
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 confidenceThe genfilt utility in AIX's Packet Filtering Module contains an integer boundary flaw where it fails to filter network traffic destined for ports greater than 32767 (0x7FFF). This allows potentially malicious traffic to bypass the packet filter on high-numbered ports.
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= 4.3.2CVSS 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
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/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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Confirm AIX version is 4.3.2Run 'oslevel' or 'oslevel -r' to display the installed AIX version and release. Also verify with 'lslpp -h bos.mp' to check the bos.mp fileset version.Affected if The version displayed is exactly 4.3.2 (not a later version like 4.3.3 or 5.x)
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Verify genfilt utility is installedRun 'lslpp -l bos.net.ipsec.rte' or 'which genfilt' to check if the Packet Filtering Module and genfilt utility are installed on the system.Affected if The genfilt command is available and the Packet Filtering Module fileset is installed
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Check if packet filtering is enabledRun 'genfilt -l' to list active filter rules. Also check 'lsfilt -v' or 'nfstat' to see if the packet filter subsystem is running.Affected if There are active filter rules configured (the filtering subsystem is in use)
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Identify filter rules handling high-numbered portsReview the output of 'genfilt -l' for any rules that specify destination or source ports greater than 32767 (0x7FFF). Look for port ranges that include ports 32768-65535.Affected if Filter rules exist that attempt to filter traffic to ports above 32767 and these rules may not be enforcing correctly due to the integer boundary flaw
You are affected only if the system is running AIX version 4.3.2 exactly AND the Packet Filtering Module with genfilt is actively used with rules that involve high-numbered ports above 32767.
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 dataApply AIX security patches for this vulnerability, or implement additional network-layer filtering at perimeter devices to control traffic to high-numbered ports until the AIX fix can be deployed.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-1999-0903 — 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-1999-0903 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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