CVE-2023-48732Network attack vector

Notification-recipient disclosure via channel-wide WebSocket broadcasts

Published Jan 2, 2024 · Updated Jun 3, 2025

Information disclosure in Mattermost 8.1.6 and earlier allows remote authenticated users to learn which channel members a post notified. SendNotifications placed per-recipient mention and follower metadata on a channel-wide WebSocket event, so every channel connection received notification-target details. Channel membership and an authenticated WebSocket session are required; exposure is limited to notification-recipient metadata, including mention-triggering keywords.

CVSS severity4.3
Medium
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Mattermost 8.1.6 and earlier allows remote authenticated users to learn which channel members a post notified. SendNotifications placed per-recipient mention and follower metadata on a channel-wide WebSocket event, so every channel connection received notification-target details. Channel membership and an authenticated WebSocket session are required; exposure is limited to notification-recipient metadata, including mention-triggering keywords.

The record

CVE
CVE-2023-48732
Published
Jan 2, 2024
Updated
Jun 3, 2025
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-200
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 2, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 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=0 <=8.1.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=8.1.6

Published CVSS scores

4.3Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
5.3GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA: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-200Exposure of Sensitive Information to an Unauthorized Actor

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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