iOSOperating system · Cisco
CVE-2015-6343
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 SIP implementation in Cisco IOS 15.5(3)M on Cisco Unified Border Element (CUBE) devices allows remote attackers to cause a denial of service via crafted SIP messages, aka Bug ID CSCuv79202.
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 denial of service vulnerability exists in the SIP implementation on Cisco Unified Border Element (CUBE) devices running IOS 15.5(3)M. Remote attackers can send specially crafted SIP messages to cause the device to become unresponsive, disrupting VoIP services.
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
= 15.5\(3\)mCVSS 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
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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 device modelRun 'show version' or 'show inventory' to confirm the hardware is Cisco Unified Border Element (CUBE)Affected if Device is not a CUBE, then not affected by this specific vulnerability
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Check the IOS versionRun 'show version' and look for the exact version string in the output. Confirm it shows '15.5(3)M' as the IOS versionAffected if IOS version is not exactly 15.5(3)M - other versions or different train identifiers are not affected by this specific CVE
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Verify SIP is enabledRun 'show sip-ua status' or 'show running-config | include sip' to check if SIP protocol is configured on the deviceAffected if SIP is not enabled or configured, the vulnerability cannot be exploited as there is no SIP processing to target
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Check device network exposureReview interface configurations and access lists to determine if the device accepts SIP traffic from untrusted external networksAffected if Device only processes SIP from trusted internal sources behind firewall, the attack surface is reduced but the vulnerability still exists in the software if version matches
The environment is affected only if the device is a Cisco Unified Border Element running exactly IOS version 15.5(3)M with SIP protocol enabled and accessible to remote attackers via network exposure to untrusted SIP 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 Cisco patch for bug CSCuv79202 (update to a patched IOS version), or implement SIP traffic filtering and rate limiting at network boundaries 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
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-6343 — 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-2015-6343 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
- No weaponised exploit code, or anything meant to cause harm
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