CVE-2023-20133Network attack vector

Stored XSS via insufficient event-content validation

Published Jul 7, 2023 · Updated Oct 23, 2024

Stored XSS in Cisco Webex Meetings allows remote authenticated users to execute script in the web interface through crafted event content. The web UI insufficiently validates user-supplied content in Webex Events (classic) programs, email templates, and survey questions before storing and rendering it. Exploitation requires an authenticated attacker and a user who follows a malicious link; resulting script runs in the affected interface and can access sensitive browser-based information.

CVSS severity5.4
Medium
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Cisco Webex Meetings allows remote authenticated users to execute script in the web interface through crafted event content. The web UI insufficiently validates user-supplied content in Webex Events (classic) programs, email templates, and survey questions before storing and rendering it. Exploitation requires an authenticated attacker and a user who follows a malicious link; resulting script runs in the affected interface and can access sensitive browser-based information.

The record

CVE
CVE-2023-20133
Published
Jul 7, 2023
Updated
Oct 23, 2024
Vendor
ClamAV
Product
Webex Meetings
Classifications
CWE-79, T1204.001, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 7, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 23, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=39.10
  2. Affected versionversion=39.11
  3. Affected versionversion=39.6
  4. Affected versionversion=39.7
  5. Affected versionversion=39.7.4
  6. Affected versionversion=39.7.7
  7. Affected versionversion=39.8
  8. Affected versionversion=39.8.2
  9. Affected versionversion=39.8.3
  10. Affected versionversion=39.8.4
  11. Affected versionversion=39.9
  12. Affected versionversion=39.9.1
  13. Affected versionversion=40.1
  14. Affected versionversion=40.2
  15. Affected versionversion=40.4
  16. Affected versionversion=40.4.10
  17. Affected versionversion=40.6
  18. Affected versionversion=40.6.2
  19. Affected versionversion=42.10
  20. Affected versionversion=42.11
  21. Affected versionversion=42.12
  22. Affected versionversion=42.6
  23. Affected versionversion=42.7
  24. Affected versionversion=42.8
  25. Affected versionversion=42.9
  26. Affected versionversion=43.1
  27. Affected versionversion=43.2
  28. Affected versionversion=43.3
  29. Affected versionversion=43.4
  30. Affected versionversion=43.4.1
  31. Affected versionversion=43.4.2
  32. Affected versionversion=43.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Webex Meetingsversion=39.10; version=39.11; version=39.6; version=39.7; version=39.7.4; version=39.7.7; version=39.8; version=39.8.2; version=39.8.3; version=39.8.4; version=39.9; version=39.9.1; version=40.1; version=40.2; version=40.4; version=40.4.10; version=40.6; version=40.6.2; version=42.10; version=42.11; version=42.12; version=42.6; version=42.7; version=42.8; version=42.9; version=43.1; version=43.2; version=43.3; version=43.4; version=43.4.1; version=43.4.2; version=43.5.0

Published CVSS scores

5.4Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:X/RL:X/RC:X

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link
T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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