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iOSOperating system · Cisco

CVE-2012-4618

HIGH · 7.8 CVSS v2.0 Published 2012-09-27
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
The SIP ALG feature in the NAT implementation in Cisco IOS 12.2, 12.4, and 15.0 through 15.2 allows remote attackers to cause a denial of service (device reload) via transit IP packets, aka Bug ID CSCtn76183.

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

The vulnerability exists in the SIP ALG (Session Initiation Protocol Application Layer Gateway) feature within the NAT implementation of Cisco IOS. Specially crafted transit IP packets processed by the SIP ALG feature can trigger a denial of service, causing the affected device to reload. The vulnerability affects Cisco IOS versions 12.2, 12.4, and 15.0 through 15.2.

MitigationIf SIP ALG is not required, disable the feature in the NAT configuration. Otherwise, upgrade to a Cisco IOS version that includes the fix for Bug ID CSCtn76183. Verify VoIP functionality works correctly after any changes.

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= 12.4= 15.0= 15.0\(1\)se= 15.1= 15.2

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 Cisco IOS version
    Execute 'show version' on the device and locate the version string in the output (e.g., 12.4, 15.1, 15.2)
    Affected if The displayed version matches 12.2, 12.4, 15.0, 15.0(1)se, 15.1, or 15.2
  2. Verify SIP ALG is enabled in NAT configuration
    Execute 'show running-config | include sip' or examine the NAT configuration section for any 'sip' keyword. SIP ALG is typically configured under 'ip nat service sip' or within NAT service settings
    Affected if SIP ALG configuration is present and active in the running configuration
  3. Confirm NAT is actively translating traffic
    Execute 'show ip nat translations' or 'show ip nat statistics' to verify NAT is actively processing traffic
    Affected if NAT translation entries exist or statistics show active translations, indicating the SIP ALG feature is processing transit packets

You are affected if your device runs a vulnerable IOS version (12.2, 12.4, 15.0-15.2) AND has SIP ALG enabled within an active NAT configuration processing traffic.

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

If SIP ALG is not required, disable the feature in the NAT configuration. Otherwise, upgrade to a Cisco IOS version that includes the fix for Bug ID CSCtn76183. Verify VoIP functionality works correctly after any changes.

Fix this in iOS Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,440
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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-2012-4618 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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