iOSOperating system · Cisco
CVE-2014-2146
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 Zone-Based Firewall (ZBFW) functionality in Cisco IOS, possibly 15.4 and earlier, and IOS XE, possibly 3.13 and earlier, mishandles zone checking for existing sessions, which allows remote attackers to bypass intended resource-access restrictions via spoofed traffic that matches one of these sessions, aka Bug IDs CSCun94946 and CSCun96847.
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 confidenceThe vulnerability exists in Cisco's Zone-Based Firewall (ZBFW) where zone membership checking is incorrectly handled for existing sessions. An attacker can bypass firewall restrictions by sending spoofed packets that match the 5-tuple of an existing valid session, allowing unauthorized traffic to pass between zones despite ZBFW policy.
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
<= 15.4\(1\)t1
Ios XeOperating system
<= 15.4\(3\)sCVSS 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
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
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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Check the installed Cisco iOS or IOS XE versionExecute 'show version' on the device and locate the version string in the output (typically displayed near the top)Affected if The version is iOS 15.4(1)T1 or earlier, or IOS XE 15.4(3)s or earlier
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Verify Zone-Based Firewall is configuredExecute 'show zone-pair security' to display ZBFW zone pairs and their security policiesAffected if Any zone-pair entries are displayed, indicating ZBFW is actively configured
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Confirm active ZBFW policy maps are in useExecute 'show policy-map type control plane' or 'show service-policy' to see if ZBFW policies are attached and actively processing trafficAffected if Policy maps are attached and actively processing traffic, meaning ZBFW is actively filtering traffic
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Examine session handling configurationExecute 'show policy-map session' or 'show zone-pair security' with session details to inspect session timeout and match criteria settingsAffected if Sessions are being created and tracked, with 5-tuple matching in use for existing connections
The device is affected if it runs Cisco iOS 15.4(1)T1 or earlier or IOS XE 15.4(3)s or earlier AND has Zone-Based Firewall actively configured with policies that process traffic between zones.
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 Cisco patches addressing Bug IDs CSCun94946 and CSCun96847, or upgrade to fixed IOS 15.4(2)T+/IOS XE 3.14+ versions. Verify ZBFW policy configurations and session timeout settings.
Fix this in iOS
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 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 $2,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2014-2146 — 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-2014-2146 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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