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ExpresswayApplication · Cisco

CVE-2021-34716

HIGH · 7.2 CVSS v3.1 Published 2021-08-18
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
78/100
Remediation priority · High
Remotely reachable Zero-click Patch available

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 web-based management interface of Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) could allow an authenticated, remote attacker to execute arbitrary code on the underlying operating system as the root user. This vulnerability is due to incorrect handling of certain crafted software images that are uploaded to the affected device. An attacker could exploit this vulnerability by authenticating to the system as an administrative user and then uploading specific crafted software images to the affected device. A successful exploit could allow the attacker to execute arbitrary code on the underlying operating system as the root user.

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

A detailed technical summary for this CVE is being prepared.

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:>= x8.6.0, < x14.1
Telepresence Video Communication ServerApplication
Affected:>= x8.6, <= x14.0.3

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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch tools.cisco.com →
Recommended fix High confidence

Cisco Expressway Series and Cisco TelePresence Video Communication Server version 14.1 or later

  1. Back up the current device configuration via the web interface or CLI
  2. Log in to Cisco Software Central (software.cisco.com) and download version 14.1 or later for your specific Expressway or VCS model
  3. Upload the software image through the web-based management interface under Maintenance > Software Upgrade, or via CLI using the command 'software upgrade'
  4. Allow the device to reboot automatically after the upgrade completes
  5. Log in to the upgraded system and verify the version under System > Information
  6. Confirm that administrative access is working and the web interface is accessible
Caveat Review Cisco release notes for version 14.1 for any configuration or feature changes before upgrading; some legacy features may have been deprecated

Generated from the published advisory — verify against the referenced sources before acting.

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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-2021-34716 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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