Ios XeOperating system · Cisco
CVE-2013-6704
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 XE does not properly manage memory for TFTP UDP flows, which allows remote attackers to cause a denial of service (memory consumption) via TFTP (1) client or (2) server traffic, aka Bug IDs CSCuh09324 and CSCty42686.
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 XE contains a memory management vulnerability in its TFTP (UDP) implementation. Remote attackers can send crafted TFTP client or server traffic to exhaust device memory, causing denial of service. The flaw affects how the OS handles UDP flows for TFTP operations.
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
Ios XeOperating system
all versionsCVSS 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
- M
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:M/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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Identify the device OS and versionRun 'show version' or 'show running-config | include ios' to confirm the device is running Cisco IOS XE and record the exact version string.Affected if The device runs any version of Cisco IOS XE and has TFTP functionality exposed.
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Check if TFTP server is enabledRun 'show running-config | include tftp' or check the configuration for 'tftp-server' commands to see if TFTP server is configured.Affected if TFTP server is enabled or configured on the device.
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Check TFTP server process statusRun 'show processes cpu history' or 'show tftp' (if available) to check if TFTP processes are active and consuming memory.Affected if TFTP server process is running and handling UDP traffic on port 69.
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Verify UDP port 69 is listeningRun 'show ip sockets' or 'show udp' to confirm the device is listening on UDP port 69 for TFTP traffic.Affected if The device has UDP port 69 open and listening for TFTP connections.
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Check network exposure of TFTP portReview access control lists and interface configurations to determine if UDP port 69 is permitted through network borders or directly accessible from untrusted networks.Affected if UDP port 69 is reachable from external or untrusted network segments.
The environment is affected if the device runs Cisco IOS XE with TFTP server enabled or TFTP port 69 exposed to network traffic, since all IOS XE versions contain the memory management flaw in the TFTP UDP implementation.
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 the relevant Cisco IOS XE security update for bug IDs CSCuh09324 and CSCty42686. If patching is delayed, restrict or disable TFTP at network borders and implement rate-limiting on UDP port 69 to limit exposure.
Fix this in Ios Xe
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-6704 — 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-2013-6704 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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