iOSOperating system · Cisco
CVE-2012-4619
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 · uneditedThe 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 CSCtr46123.
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 confidenceA vulnerability in the NAT (Network Address Translation) implementation in Cisco IOS versions 12.2, 12.4, and 15.0 through 15.2 allows remote, unauthenticated attackers to send specially crafted transit IP packets that cause the affected device to reload, resulting in denial of service.
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
= 12.2= 12.4= 15.0= 15.0\(1\)se= 15.1= 15.2CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify the Cisco IOS versionExecute 'show version' on the device CLI and locate the IOS release number in the outputAffected if The version displayed matches 12.2, 12.4, 15.0, 15.0(1)se, 15.1, or 15.2
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Verify NAT is configuredRun 'show running-config | include ip nat' or 'show ip nat statistics' to check for active NAT configurationAffected if NAT is enabled and there are active NAT translations or NAT pool configurations present
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Confirm NAT is applied to external interfacesExamine the running configuration for interface entries containing 'ip nat inside' or 'ip nat outside' on any WAN or external-facing interfacesAffected if NAT is bound to interfaces that handle transit traffic from untrusted networks
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Check for existing ACL filtering on NAT interfacesReview interface configurations and ACL entries to determine if transit traffic through NAT interfaces is restricted by access listsAffected if No ACLs are applied to filter inbound transit traffic on NAT-enabled interfaces, leaving the device exposed to crafted packets
The environment is affected if the device runs an affected IOS version (12.2, 12.4, 15.0-15.2) and has NAT enabled on interfaces that process untrusted transit traffic.
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 appropriate Cisco IOS software update or upgrade to a fixed version. If immediate patching is not possible, consider implementing ACLs on external interfaces to restrict transit traffic or disable NAT on unused interfaces to reduce attack surface.
Fix this in iOS
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-4619 — 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-2012-4619 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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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.
- 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
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