CVE-2023-28357Network attack vector

Private-channel membership disclosure via late ACL check

Published May 11, 2023 · Updated Jan 27, 2025

Incorrect authorization in Rocket.Chat before 6.0 allows remote authenticated users to enumerate members of inaccessible private channels. The /mute slash command checks whether a supplied username belongs to the target channel before it enforces the caller's channel access control. Any authenticated account can use the response difference to confirm a user's membership in a private channel it cannot access, disclosing membership only.

CVSS severity4.3
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Rocket.Chat before 6.0 allows remote authenticated users to enumerate members of inaccessible private channels. The /mute slash command checks whether a supplied username belongs to the target channel before it enforces the caller's channel access control. Any authenticated account can use the response difference to confirm a user's membership in a private channel it cannot access, disclosing membership only.

The record

CVE
CVE-2023-28357
Published
May 11, 2023
Updated
Jan 27, 2025
Vendor
Rocket.Chat Technologies Corp.
Product
Rocket.Chat
Classifications
CWE-863, CWE-200, T1087
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 27, 2025Record 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=This issue has been fixed in version 6.0> and is backported for the supported versions. Check this document for more info: https://docs.rocket.chat/resources/get-support/enterprise-support#rocket.chat-versions

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Rocket.Chat Technologies Corp. · Rocket.Chatversion=This issue has been fixed in version 6.0> and is backported for the supported versions. Check this document for more info: https://docs.rocket.chat/resources/get-support/enterprise-support#rocket.chat-versions

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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-863Incorrect Authorization
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1087Account Discovery

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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