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iOSOperating system · Cisco

CVE-2013-5473

HIGH · 7.8 CVSS v2.0 Published 2013-09-27
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
Memory leak in Cisco IOS 12.2, 15.1, and 15.2; IOS XE 3.4.2S through 3.4.5S; and IOS XE 3.6.xS before 3.6.1S allows remote attackers to cause a denial of service (memory consumption or device reload) via malformed IKEv1 packets, aka Bug ID CSCtx66011.

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 memory leak vulnerability in Cisco IOS and IOS XE allows remote attackers to cause denial of service by sending malformed IKEv1 packets, leading to memory exhaustion and potential device reload.

MitigationApply the appropriate Cisco security update (IOS XE 3.6.1S or later) for your version, or implement ingress filtering for IKEv1 traffic at network boundaries to block malformed packets.

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:= 12.2= 15.1= 15.2
Ios XeOperating system
Affected:= 3.4.2s= 3.4.3s= 3.4.4s= 3.4.5s= 3.6.0s

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 exact IOS/IOS XE version
    Execute 'show version' on the device CLI and locate the 'IOS XE Software' or 'IOS Software' version string (for example, Version 15.2(4)E or Version 3.4.2S)
    Affected if The displayed version matches or falls within these ranges: Cisco iOS 12.2.x, 15.1.x, 15.2.x; Cisco IOS XE 3.4.2S through 3.6.0S
  2. Confirm IKEv1 is configured
    Run 'show running-config | include isakmp' or 'show crypto isakmp sa' to see if ISAKMP/IKEv1 is enabled
    Affected if IKEv1 (ISAKMP) policies or security associations are present in the configuration or active on the device
  3. Check for active IKEv1 sessions
    Execute 'show crypto session' or 'show crypto isakmp sa detail' to list current IKEv1 tunnels
    Affected if Any IKEv1 tunnels are currently active, as the vulnerability triggers when malformed packets are processed through active sessions
  4. Monitor memory usage for depletion
    Run 'show process memory' or 'show memory summary' and compare current free memory to baseline levels
    Affected if Free memory shows significant depletion or the 'Processor' pool free memory is abnormally low, indicating the leak may be active
  5. Review IKEv1 packet error counters
    Execute 'show crypto isakmp error' or check interface packet counters for IKEv1-related errors
    Affected if Unusual or increasing error counters related to IKEv1 packet processing are present

The device is affected if it runs a matching IOS/IOS XE version, has IKEv1 configured or active, and is experiencing abnormal memory consumption or IKEv1-related errors from incoming malformed packets.

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 appropriate Cisco security update (IOS XE 3.6.1S or later) for your version, or implement ingress filtering for IKEv1 traffic at network boundaries to block malformed packets.

Fix this in iOS Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,740
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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-2013-5473 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
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  • Version or environment caveats, and links to real fixes
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