Webex Meetings ServerApplication · Cisco
CVE-2020-3471
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 · uneditedA vulnerability in Cisco Webex Meetings and Cisco Webex Meetings Server could allow an unauthenticated, remote attacker to maintain bidirectional audio despite being expelled from an active Webex session. The vulnerability is due to a synchronization issue between meeting and media services on a vulnerable Webex site. An attacker could exploit this vulnerability by sending crafted requests to a vulnerable Cisco Webex Meetings or Cisco Webex Meetings Server site. A successful exploit could allow the attacker to maintain the audio connection of a Webex session despite being expelled.
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 synchronization flaw in Cisco Webex Meetings allows expelled users to maintain bidirectional audio connections. The meeting service and media service lack proper state synchronization—when a user is expelled from the meeting, the media service continues to carry the audio stream, enabling the expelled participant to continue listening despite being removed from the session.
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
Webex Meetings ServerApplication
< 3.0= 3.0= 4.0CVSS 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:3.1/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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Identify installed Cisco Webex Meetings Server versionAccess the Webex Meetings Server admin interface or run the command 'show version' via CLI to retrieve the currently installed software versionAffected if The installed version is less than 3.0, exactly 3.0, or exactly 4.0
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Verify media service is runningCheck the status of the Webex media service process using system monitoring tools or admin console - look for processes related to audio/media handlingAffected if Media service is active and handling meeting audio streams
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Review meeting session configurationExamine the Webex Meetings Server configuration for session management settings, specifically the synchronization parameters between meeting service and media serviceAffected if Session state synchronization between meeting and media services is not explicitly configured or documented as patched
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Test user expulsion behaviorCreate a test meeting, join with two participants, then expel one participant while monitoring network connections from the expelled client sideAffected if The expelled participant retains an active audio connection and can still hear meeting audio after removal from the session
A user is affected if their Cisco Webex Meetings Server is version 3.0 or 4.0 (or earlier than 3.0) and expelled participants can continue hearing meeting audio after removal.
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 data3.0
Apply Cisco's patches for Webex Meetings and Webex Meetings Server as they become available; verify that expelled users cannot retain audio connectivity through manual testing.
Fix this in Webex Meetings Server
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 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 $1,904.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3471 — 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-2020-3471 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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