iOSOperating system · Cisco
CVE-2016-1347
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 Wide Area Application Services (WAAS) Express implementation in Cisco IOS 15.1 through 15.5 allows remote attackers to cause a denial of service (device reload) via a crafted TCP segment, aka Bug ID CSCuq59708.
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 · moderate confidenceA remote unauthenticated attacker can send specially crafted TCP segments to a Cisco device running WAAS Express (IOS versions 15.1 through 15.5), causing the device to reload and experience denial of service. The vulnerability is in the WAAS Express implementation and can be triggered by malformed TCP 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
= 15.1\(4\)gc2= 15.1\(4\)m6= 15.1\(4\)xb4= 15.1\(4\)xb5= 15.1\(4\)xb5a= 15.1\(4\)xb6= 15.1\(4\)xb7= 15.1\(4\)xb8= 15.1\(4\)xb8a= 15.2\(4\)jaz1= 15.2\(4\)m7= 15.3\(1\)t2CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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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Verify if WAAS Express is enabledExecute 'show waas express status' or 'show ip wccp' command on the Cisco device to check if WAAS Express feature is activeAffected if WAAS Express is enabled and running on the device (the vulnerability only affects devices with WAAS Express active)
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Check the running Cisco iOS versionExecute 'show version' command to display the installed Cisco iOS version and build numberAffected if The iOS version matches or falls within the affected build ranges: 15.1(4)gc2, 15.1(4)m6, 15.1(4)xb4, 15.1(4)xb5, 15.1(4)xb5a, 15.1(4)xb6, 15.1(4)xb7, 15.1(4)xb8, 15.1(4)xb8a, 15.2(4)jaz1, 15.2(4)m7, 15.3(1)t2, or any version from 15.1 through 15.5 containing WAAS Express
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Confirm WAAS Express TCP processing is exposedReview the device configuration with 'show running-config | include waas' to verify WAAS Express is configured to process TCP trafficAffected if WAAS Express is configured to handle TCP connections, making the malformed packet handling code reachable
The device is affected if WAAS Express is enabled AND the iOS version falls within 15.1 through 15.5 (specifically the listed build numbers), as the vulnerability requires both conditions to be present for remote unauthenticated attackers to trigger the denial of service via malformed TCP packets.
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 dataUpgrade to a patched Cisco IOS version beyond 15.5, or disable WAAS Express if not required, or implement network-layer access controls to filter untrusted TCP traffic destined to affected devices.
Fix this in iOS
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 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 $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-1347 — 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-2016-1347 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
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