CVE-2001-0498
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 · uneditedTransparent Network Substrate (TNS) over Net8 (SQLNet) in Oracle 8i 8.1.7 and earlier allows remote attackers to cause a denial of service via a malformed SQLNet connection request with a large offset in the header extension.
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 confidenceOracle 8i TNS (Transparent Network Substrate) / Net8 (SQLNet) contains a denial of service vulnerability triggered by malformed SQLNet connection requests containing a large offset value in the header extension. Remote attackers can send specially crafted packets to crash the Oracle listener or database service, causing availability disruption.
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<= 8.1.7CVSS 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
- Partial
AV:N/AC:L/Au:N/C:N/I:N/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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Identify the installed Oracle database versionRun 'lsnrctl status' to check the listener version, or connect via SQL*Plus and run 'SELECT VERSION FROM V$INSTANCE;' to get the exact Oracle versionAffected if The version returned is 8.1.7 or any 8.1.x version lower than 8.1.7 (8.1.0 through 8.1.6)
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Verify the TNS listener is runningExecute 'lsnrctl status' or 'lsnrctl service' to confirm the Oracle Net8/TNS listener process is activeAffected if The listener is running and responding to connection requests
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Determine if the TNS listener is network-exposedCheck which network interfaces the listener is bound to by reviewing the listener.ora file or running 'lsnrctl status' to see the listening addresses, or use 'netstat -an | grep 1521' to check if port 1521 (default TNS port) is listening on external interfacesAffected if The listener is bound to 0.0.0.0 or a routable IP address rather than only 127.0.0.1 (localhost)
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Confirm the vulnerable SQLNet protocol is enabledThe vulnerability exists in the SQLNet/TNS connection handling. By default, Oracle 8i accepts SQLNet connections on port 1521. Verify acceptance of SQLNet connections is not disabled in listener.oraAffected if SQLNet/TNS listener is enabled and accepting connections on the network
If your environment runs Oracle 8i version 8.1.7 or lower with the TNS listener exposed to the network, you are affected by this vulnerability and should apply Oracle's patch or upgrade to a supported version.
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 Oracle Critical Patch Updates for this vulnerability or upgrade to a supported Oracle version. Network segmentation and firewall rules can reduce exposure to unauthenticated network-based attacks.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2001-0498 — 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-2001-0498 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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