CVE-2002-0163
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 · uneditedHeap-based buffer overflow in Squid before 2.4 STABLE4, and Squid 2.5 and 2.6 until March 12, 2002 distributions, allows remote attackers to cause a denial of service, and possibly execute arbitrary code, via compressed DNS responses.
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 confidenceHeap-based buffer overflow in Squid's DNS response parsing code. When processing compressed DNS responses, Squid fails to properly validate buffer lengths before copying data, allowing an attacker to overflow the heap and potentially execute arbitrary code or cause 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<= 2.4_9CVSS 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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Identify Squid versionRun 'squid -v' or 'squid -V' to display the installed Squid version numberAffected if The displayed version is 2.4.x where x is less than or equal to 9 (for example 2.4.9, 2.4.8, 2.4.7, etc.) or shows 2.4_9 or earlier
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Confirm DNS lookup functionality is in useInspect the Squid configuration file (commonly /etc/squid/squid.conf or /etc/squid3/squid.conf) for any 'dns_nameservers' directive or other DNS-related settingsAffected if The configuration contains directives that enable Squid to perform DNS lookups (such as dns_nameservers), meaning Squid will parse incoming DNS responses
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Verify if Squid is accessible to untrusted networksCheck network listening status via 'netstat -anp | grep squid' or 'ss -anp | grep squid' and review firewall rulesAffected if Squid is bound to 0.0.0.0 or an IP accessible from untrusted networks, increasing exposure to remote DNS response attacks
You are affected if Squid version is 2.4_9 or earlier AND Squid is configured to perform DNS lookups AND the service is reachable from untrusted networks.
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 Squid 2.4 STABLE4 or later, or apply the vendor-supplied patch. As an interim control, restrict network access to the Squid service to trusted sources.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2002-0163 — 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-2002-0163 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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- 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
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