Telepresence Video Communication Server SoftwareApplication · Cisco
CVE-2016-1338
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 · uneditedCisco TelePresence Video Communication Server (VCS) X8.5.1 and X8.5.2 allows remote authenticated users to cause a denial of service (VoIP outage) via a crafted SIP message, aka Bug ID CSCuu43026.
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 confidenceCisco TelePresence VCS X8.5.1 and X8.5.2 contain a vulnerability where authenticated remote users can send specially crafted SIP (Session Initiation Protocol) messages that cause the VoIP service to fail, resulting in a denial of service and VoIP outage.
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
Telepresence Video Communication Server SoftwareApplication
= x8.5.1= x8.5.2CVSS 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
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:L/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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Identify the Cisco TelePresence VCS versionLog into the VCS admin interface and navigate to System > About or use the CLI command 'xstatus version' to determine the exact software version installedAffected if The installed version is exactly X8.5.1 or X8.5.2
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Verify SIP service is enabledCheck the VCS configuration under SIP > SIP Settings or the SIP proxy configuration to confirm the SIP service is active and listening for connectionsAffected if SIP service is enabled and reachable on the VCS
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Confirm SIP is exposed to networkReview the VCS firewall rules, SIP listen addresses, or the Allow list under SIP > Configuration to determine if SIP ports (5060/5061) are open to untrusted networksAffected if SIP is accessible from networks that include untrusted or unknown users
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Check authentication configuration for SIPExamine the SIP authentication settings under SIP > Authentication to determine whether remote users are required to authenticate before sending SIP messagesAffected if SIP authentication is not enforced or allows unauthenticated/weak authentication for remote users
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Review for service disruptionsCheck the VCS event logs or system status under Logs > Event Log for recent SIP-related crashes, service failures, or unexpected restarts of the VoIP serviceAffected if There are recent SIP crash logs or VoIP service failures that match the timing of potential exploitation
If the installed version is exactly X8.5.1 or X8.5.2 and the SIP service is enabled and accessible to remote users, the environment is vulnerable to this denial-of-service flaw.
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 Cisco TelePresence VCS to a version beyond X8.5.2 that includes the fix for CSCuu43026. If immediate upgrade is not possible, restrict SIP access to trusted endpoints and monitor for service disruptions.
Fix this in Telepresence Video Communication Server Software
Scoped from the published advisory
- Consultation4.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-1338 — 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-2016-1338 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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