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iOSOperating system · Cisco

CVE-2013-5553

HIGH · 7.8 CVSS v2.0 Published 2013-11-08
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
Multiple memory leaks in Cisco IOS 15.1 before 15.1(4)M7 allow remote attackers to cause a denial of service (memory consumption or device reload) by sending a crafted SIP message over (1) IPv4 or (2) IPv6, aka Bug IDs CSCuc42558 and CSCug25383.

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

Multiple memory leaks exist in Cisco IOS 15.1 before version 15.1(4)M7 when processing crafted SIP (Session Initiation Protocol) messages over IPv4 or IPv6. Successful exploitation allows remote attackers to cause memory exhaustion leading to device reload or denial of service. The vulnerability is in the SIP protocol handling subsystem.

MitigationUpgrade Cisco IOS to version 15.1(4)M7 or later. If immediate upgrade is not feasible, consider implementing SIP traffic filtering at network perimeter or deploying intrusion prevention to block malformed SIP messages.

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:= 15.1

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. Check Cisco IOS version
    Run 'show version' command and look at the version line. Identify if the IOS version starts with '15.1' and compare it to the affected range (15.1 before 15.1(4)M7)
    Affected if The version is 15.1 or any 15.1.x release before 15.1(4)M7
  2. Verify SIP protocol support is enabled
    Run 'show sip' or check the running configuration for any 'sip' related commands such as 'sip enable', 'voice service voip', or 'sip' under voice class configurations
    Affected if SIP protocol handling subsystem is enabled on the device
  3. Check for active SIP calls or registrar
    Run 'show sip calls' or 'show sip status' to see if the device is actively processing SIP sessions
    Affected if The device is actively processing SIP calls or acting as a SIP registrar/proxy
  4. Confirm SIP transport configuration
    Run 'show sip transport' to check if SIP is bound to IPv4, IPv6, or both transport interfaces
    Affected if SIP is configured to handle traffic over IPv4 or IPv6 (or both)
  5. Check for memory leak indicators
    Run 'show memory statistics' or 'show process memory' repeatedly over time, focusing on the SIP-related process memory usage
    Affected if Memory usage continuously increases for SIP-related processes when receiving SIP traffic

A device is affected if it runs Cisco IOS version 15.1 before 15.1(4)M7 AND has SIP protocol enabled to process SIP messages over IPv4 or IPv6.

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

Upgrade Cisco IOS to version 15.1(4)M7 or later. If immediate upgrade is not feasible, consider implementing SIP traffic filtering at network perimeter or deploying intrusion prevention to block malformed SIP messages.

Fix this in iOS Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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Scan for this in your stack

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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-2013-5553 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data