CVE-2020-3126Network attack vector

Malicious content rendering via missing warning dialog

Published Apr 13, 2020 · Updated Nov 15, 2024

Improper access control in Cisco Webex Meetings T39.3 allows remote authenticated users to render malicious multimedia in a former host's browser. The Multimedia Viewer omits the security warning that normally precedes display when a former room host opens a file shared by the current host. Exploitation requires host privileges and user interaction by the former host, exposing the browser window to attacker-supplied multimedia.

CVSS severity3.0
Low
EPSS probability0.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Cisco Webex Meetings T39.3 allows remote authenticated users to render malicious multimedia in a former host's browser. The Multimedia Viewer omits the security warning that normally precedes display when a former room host opens a file shared by the current host. Exploitation requires host privileges and user interaction by the former host, exposing the browser window to attacker-supplied multimedia.

The record

CVE
CVE-2020-3126
Published
Apr 13, 2020
Updated
Nov 15, 2024
Vendor
Cisco
Product
Cisco Webex Meetings
Classifications
CWE-20, CWE-284, T1204.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 13, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=T39.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Cisco · Cisco Webex Meetingsversion=T39.3

Published CVSS scores

3.5NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
3.0Cisco Systems, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:L/A:N
3.5NISTAV:N/AC:M/Au:S/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-284Improper Access Control
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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