CVE-2023-5193Network attack vector

DM post disclosure via incorrect permission check

Published Sep 29, 2023 · Updated Sep 20, 2024

Incorrect authorization in Mattermost 7.8.9 and earlier, 8.0.1 and earlier, and 8.1.0 allows remote authenticated users to read DM posts. The post-retrieval authorization path accepts the system-level manage-channels permission without requiring membership in the direct-message channel. Exploitation requires a System Role carrying that permission and a target post identifier; it discloses conversation content without changing messages.

CVSS severity4.9
Medium
EPSS probability0.47%
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 Mattermost 7.8.9 and earlier, 8.0.1 and earlier, and 8.1.0 allows remote authenticated users to read DM posts. The post-retrieval authorization path accepts the system-level manage-channels permission without requiring membership in the direct-message channel. Exploitation requires a System Role carrying that permission and a target post identifier; it discloses conversation content without changing messages.

The record

CVE
CVE-2023-5193
Published
Sep 29, 2023
Updated
Sep 20, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-863, T1213.005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 29, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 20, 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 <=7.8.9
  2. Affected versionversion=0 <=8.0.1
  3. Affected versionversion=8.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=7.8.9; version=0 <=8.0.1; version=8.1.0

Published CVSS scores

4.9Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
2.7NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/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
T1213.005Data from Information Repositories: Messaging Applications

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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