Webex MeetingsApplication · Cisco
CVE-2020-3440
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 Desktop App for Windows could allow an unauthenticated, remote attacker to overwrite arbitrary files on an end-user system. The vulnerability is due to improper validation of URL parameters that are sent from a website to the affected application. An attacker could exploit this vulnerability by persuading a user to follow a URL to a website that is designed to submit crafted input to the affected application. A successful exploit could allow the attacker to overwrite arbitrary files on the affected system, possibly corrupting or deleting critical system files.
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 confidenceThis is a file write vulnerability in Cisco Webex Meetings Desktop App for Windows stemming from improper validation of URL parameters received from websites. An attacker can craft malicious URLs that, when clicked by a user, cause the Webex application to write arbitrary files to the victim's file system, potentially overwriting or deleting critical system files.
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 MeetingsApplication
< 40.8CVSS 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
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/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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Verify Cisco Webex Meetings Desktop App for Windows is installedOpen Windows Settings > Apps & Features, or use Control Panel > Programs and Features, and search for 'Cisco Webex' or 'Webex Meetings'. Alternatively, check for the presence of Webex executable in common installation directories.Affected if The application is not found in installed programs or no Webex installation directory exists.
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Identify the installed Webex Meetings version numberRight-click the Webex executable (typically named 'WebexMeetingsApp.exe' or similar) in the installation folder, select Properties, then view the Details tab for the Product Version field. Alternatively, check the Windows Registry under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall for a Webex entry and read the DisplayVersion value.Affected if No version information is returned or the application is not found in registry uninstall entries.
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Compare installed version against the affected thresholdTake the identified version number from step 2 and compare it numerically to version 40.8. Any version starting with 40.7, 40.6, or lower, or any 39.x.x or earlier release, falls within the vulnerable range.Affected if The installed version is less than 40.8 (for example, 40.7.x, 40.6.x, 39.x.x, etc.).
If Cisco Webex Meetings Desktop App for Windows is installed and the version is below 40.8, the environment is affected by this file write vulnerability.
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 data40.8
Apply vendor-supplied patches for Cisco Webex when available. Until then, warn users against clicking untrusted links and consider network-level controls to block suspicious URL patterns targeting webex protocols.
Fix this in Webex Meetings
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 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-2020-3440 — 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-2020-3440 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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- Version or environment caveats, and links to real fixes
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