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ExpresswayApplication · Cisco

CVE-2020-3482

MEDIUM · 6.5 CVSS v3.1 Published 2020-11-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
74/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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 · unedited
A vulnerability in the Traversal Using Relays around NAT (TURN) server component of Cisco Expressway software could allow an unauthenticated, remote attacker to bypass security controls and send network traffic to restricted destinations. The vulnerability is due to improper validation of specific connection information by the TURN server within the affected software. An attacker could exploit this issue by sending specially crafted network traffic to the affected software. A successful exploit could allow the attacker to send traffic through the affected software to destinations beyond the application, possibly allowing the attacker to gain unauthorized network access.

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 confidence

A vulnerability in the TURN (Traversal Using Relays around NAT) server component of Cisco Expressway allows an unauthenticated remote attacker to bypass security controls by sending specially crafted network traffic with improper connection information. This enables traffic relay to destinations beyond the intended network boundaries, potentially granting unauthorized network access.

MitigationApply the Cisco-provided patch for Cisco Expressway software; until then, restrict TURN server exposure to untrusted networks and monitor for unusual relay traffic patterns.

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
ExpresswayApplication
Affected:< x12.6.3
Telepresence Video Communication ServerApplication
Affected:< x12.6.3

CVSS 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
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed product
    Log into the Cisco Expressway or Telepresence Video Communication Server admin interface and navigate to System > System Information to confirm the product name and exact version number.
    Affected if Product is Cisco Expressway or Cisco Telepresence VCS with version below x12.6.3
  2. Compare version to affected range
    Locate the Version field in the System Information page and compare it against x12.6.3. Note that versions are typically displayed as major.minor.patch (e.g., x12.5, x12.6).
    Affected if Installed version is x12.6.2 or lower, or any version in the x12.5 or earlier train
  3. Confirm TURN server is enabled
    In the admin interface, navigate to Configuration > Traversal > TURN and verify the TURN server status. Alternatively, use the CLI command 'turn server status' if SSH access is available.
    Affected if TURN server status shows as Enabled or Running
  4. Check TURN server network exposure
    Review firewall rules or access lists that govern which IP networks can reach the TURN server UDP/TCP ports (typically 3478 for STUN/TURN, 3479-3483 for TURN media). Determine if the TURN server listens on interfaces accessible from untrusted/external networks.
    Affected if TURN server is reachable from networks outside the trusted internal network

You are affected if you are running Cisco Expressway or Telepresence VCS version x12.6.2 or below with the TURN server enabled and exposed to untrusted networks.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco-provided patch for Cisco Expressway software; until then, restrict TURN server exposure to untrusted networks and monitor for unusual relay traffic patterns.

Fix this in Expressway Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA6.0 h
30.0 hours of engineering $5,120
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-3482 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data