iOSOperating system · Cisco
CVE-2009-5038
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 · uneditedCisco IOS before 15.0(1)XA does not properly handle IRC traffic during a specific time period after an initial reload, which allows remote attackers to cause a denial of service (device reload) via an attempted connection to a certain IRC server, related to a "corrupted magic value," aka Bug ID CSCso05336.
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 confidenceCisco IOS versions before 15.0(1)XA contain a flaw in handling IRC traffic during a specific time window after a device reload. A corrupted magic value triggered by attempted IRC server connections causes the device to reload, resulting in 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
iOSOperating system
< 15.0\(1\)xaCVSS 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
- Complete
AV:N/AC:L/Au:N/C:N/I:N/A:C
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 the Cisco IOS versionExecute 'show version' or 'show ios version' on the device to display the installed IOS versionAffected if The version is earlier than 15.0(1)XA (such as 12.x or 14.x releases)
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Verify if IRC traffic handling is configuredCheck for IRC-related configurations using 'show running-config | include irc' or review access-lists and policy maps that may reference IRC ports (TCP 6667)Affected if IRC server access or IRC traffic inspection is enabled on the device
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Determine time since last reloadExecute 'show version' to check 'System returned to ROM by' or 'System restarted' timestamp, or use 'show clock' and compare to boot time from 'show startup-config'Affected if The device was reloaded within the vulnerable time window (specific timing not defined in advisory, but window exists post-reload)
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Review crash logs or reload historyExecute 'show crashinfo' or 'show log' to examine recent reload reasons, looking for unexpected reloads that may correlate with IRC trafficAffected if Unexplained reloads occurred after IRC server connections were attempted
The device is affected if it runs Cisco IOS versions before 15.0(1)XA, has IRC traffic handling configured, and is operating within the vulnerable time window after a device reload.
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 data15.0
Upgrade Cisco IOS to version 15.0(1)XA or later to resolve the corrupted magic value issue in IRC traffic processing.
Fix this in iOS
Scoped from the published advisory
- Consultation3.0 h
- Implementation2.0 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 $2,784.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2009-5038 — 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-2009-5038 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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