CVE-2023-36539Network attack vector

Chat disclosure via omitted per-meeting encryption

Published Jun 30, 2023 · Updated Oct 28, 2024

Missing encryption in affected Zoom Clients allows remote authenticated users to read E2EE in-meeting chat messages. The clients send a second copy of each in-meeting chat message under TLS alone, omitting the meeting-specific key even in E2EE meetings. Exploitation requires low privileges and high complexity; confidentiality loss is the only published consequence.

CVSS severity5.3
Medium
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing encryption in affected Zoom Clients allows remote authenticated users to read E2EE in-meeting chat messages. The clients send a second copy of each in-meeting chat message under TLS alone, omitting the meeting-specific key even in E2EE meetings. Exploitation requires low privileges and high complexity; confidentiality loss is the only published consequence.

The record

CVE
CVE-2023-36539
Published
Jun 30, 2023
Updated
Oct 28, 2024
Vendor
Zoom Video Communications, Inc.
Product
Zoom Clients
Classifications
CWE-325, CWE-200, T1040
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 30, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 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=See references link for ZSB-23025

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zoom Video Communications, Inc. · Zoom Clientsversion=See references link for ZSB-23025

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.3Zoom Video Communications, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/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-325Missing Cryptographic Step
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1040Network Sniffing

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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