CVE-2009-4500
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 process_trap function in trapper/trapper.c in Zabbix Server before 1.6.6 allows remote attackers to cause a denial of service (crash) via a crafted request with data that lacks an expected : (colon) separator, which triggers a NULL pointer 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 · high confidenceThe process_trap function in Zabbix Server's trapper.c crashes due to a NULL pointer dereference when processing a specially crafted request that lacks an expected colon (:) separator in the data. This causes a denial of service condition.
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<= 1.4.6= 1.1.2= 1.1.3= 1.1.4= 1.1.5= 1.4.2= 1.4.3= 1.4.4CVSS 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 if Zabbix Server is installedRun command 'zabbix_server -V' or check package manager for zabbix-server (e.g., dpkg -l | grep zabbix, rpm -qa | grep zabbix)Affected if No zabbix-server package is found, meaning the product is not installed and therefore not affected
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Determine the installed Zabbix Server versionExecute 'zabbix_server -V' to display the version number, or query the package databaseAffected if The version matches one of the affected versions: 1.1.2, 1.1.3, 1.1.4, 1.1.5, 1.4.2, 1.4.3, 1.4.4, or any version 1.4.6 or lower
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Verify the trapper functionality is enabledCheck the Zabbix Server configuration file (typically zabbix_server.conf) for the 'StartTrappers' parameter and confirm it is set to a value greater than 0, or check if port 10051 (default trapper port) is listeningAffected if StartTrappers is set to a non-zero value or port 10051 is open and accepting connections, meaning the vulnerable process_trap function is active
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Confirm the server is accessible over the trapper portUse 'netstat -tulpn' or 'ss -tulpn' to verify that port 10051 is in LISTEN state and bound to the zabbix_server processAffected if Port 10051 is listening, indicating the trapper component is exposed and could receive the specially crafted request lacking the colon separator
A user is affected if Zabbix Server version 1.1.2-1.1.5, 1.4.2-1.4.4, or 1.4.5-1.4.6 is installed with the trapper component enabled (StartTrappers > 0) and the trapper port is accessible.
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 Zabbix Server to version 1.6.6 or later, which contains the fix for proper input validation in the process_trap function.
- Consultation2.0 h
- Implementation3.0 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-2009-4500 — 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-2009-4500 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
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