CVE-2023-43754Network attack vector

Archived-channel disclosure via missing permalink authorization check

Published Nov 27, 2023 · Updated Aug 2, 2024

Information disclosure in Mattermost 7.8.12, 8.1.3, 9.0.1, and 9.1.0 allows remote authenticated users to view archived post previews. The permalink-preview path omits the authorization check for the “Allow users to view archived channels” setting and renders previews despite its disabled state. Membership access is required, and exposure is limited to archived-channel content reachable through a permalink preview, with no reported write or availability impact.

CVSS severity4.3
Medium
EPSS probability0.51%
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 7.8.12, 8.1.3, 9.0.1, and 9.1.0 allows remote authenticated users to view archived post previews. The permalink-preview path omits the authorization check for the “Allow users to view archived channels” setting and renders previews despite its disabled state. Membership access is required, and exposure is limited to archived-channel content reachable through a permalink preview, with no reported write or availability impact.

The record

CVE
CVE-2023-43754
Published
Nov 27, 2023
Updated
Aug 2, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-200, T1213.005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 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=0 <=7.8.12
  2. Affected versionversion=0 <=8.1.3
  3. Affected versionversion=0 <=9.0.1
  4. Affected versionversion=0 <=9.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=7.8.12; version=0 <=8.1.3; version=0 <=9.0.1; version=0 <=9.1.0

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

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-200Exposure of Sensitive Information to an Unauthorized Actor
T1213.005Messaging

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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