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iOSOperating system · Cisco

CVE-2014-3357

HIGH · 7.8 CVSS v2.0 Published 2014-09-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
Cisco IOS 15.0, 15.1, 15.2, and 15.4 and IOS XE 3.3.xSE before 3.3.2SE, 3.3.xXO before 3.3.1XO, 3.5.xE before 3.5.2E, and 3.11.xS before 3.11.1S allow remote attackers to cause a denial of service (device reload) via malformed mDNS packets, aka Bug ID CSCul90866.

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 confidence

A denial of service vulnerability in Cisco IOS 15.0-15.4 and IOS XE allows remote attackers to cause device reload by sending malformed mDNS (multicast DNS) packets. The vulnerability is triggered when the device processes specially crafted mDNS packets, leading to a system crash and reload.

MitigationApply the vendor-supplied patches (IOS XE 3.3.2SE, 3.3.1XO, 3.5.2E, 3.11.1S or later). If immediate patching is not feasible, filter or block mDNS traffic at network boundaries using ACLs to reduce exposure.

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
Affected:= 15.0= 15.1= 15.2= 15.4
Ios XeOperating system
Affected:= 3.3\(.0\)xo= 3.3.0se= 3.3.1se= 3.5.0e= 3.5.1e= 3.11.0s

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Cisco IOS or IOS XE version
    Execute 'show version' on the device CLI and locate the version string in the output (typically in the first few lines, e.g., 'Cisco IOS Software, Version 15.2' or 'Cisco IOS XE Software, Version 3.3.1SE')
    Affected if The version falls within these ranges: IOS 15.0, 15.1, 15.2, or 15.4; IOS XE 3.3.0XO, 3.3.0SE, 3.3.1SE, 3.5.0E, 3.5.1E, or 3.11.0S
  2. Confirm the device is running IOS or IOS XE
    The 'show version' output will indicate whether the device runs 'IOS' or 'IOS XE' - this determines which version range applies
    Affected if The device runs Cisco IOS or IOS XE and the version matches the affected ranges listed above
  3. Determine if mDNS (multicast DNS) service is enabled
    Run 'show running-config | include mdns' or 'show ip mdns cache' to check for mDNS configuration; also look for 'service mdns' or 'mdns gateway' in the running configuration
    Affected if mDNS gateway, service mdns, or mdns-sd configuration appears in the running config, indicating the feature is active
  4. Assess network exposure to mDNS traffic
    Check interface configurations and ACLs with 'show ip interface' and 'show access-lists' to determine if the device accepts mDNS packets (typically UDP port 5353) from untrusted sources
    Affected if The device has interfaces that can receive mDNS packets from external or untrusted networks without filtering ACLs blocking UDP port 5353

The device is affected if it runs a vulnerable IOS or IOS XE version (15.0-15.4 for IOS, or the listed XE versions) AND has mDNS gateway or service enabled AND can receive mDNS traffic from network segments that could contain malicious attackers.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor-supplied patches (IOS XE 3.3.2SE, 3.3.1XO, 3.5.2E, 3.11.1S or later). If immediate patching is not feasible, filter or block mDNS traffic at network boundaries using ACLs to reduce exposure.

Fix this in iOS Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2014-3357 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data