CVE-2021-37864Network attack vector

Archived-channel disclosure via missing API permission checks

Published Jan 18, 2022 · Updated Dec 6, 2024

Incorrect authorization in Mattermost Server 6.1 and earlier allows remote authenticated users to read archived channel content via APIs. API paths serving archived channels fail to enforce the administrator-controlled archived-channel viewing restriction before returning channel data. An account and a deployment with archived-channel viewing disabled are required; exposure is limited to archived channel content.

CVSS severity6.5
Medium
EPSS probability0.58%
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 Server 6.1 and earlier allows remote authenticated users to read archived channel content via APIs. API paths serving archived channels fail to enforce the administrator-controlled archived-channel viewing restriction before returning channel data. An account and a deployment with archived-channel viewing disabled are required; exposure is limited to archived channel content.

The record

CVE
CVE-2021-37864
Published
Jan 18, 2022
Updated
Dec 6, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-284, CWE-863, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 18, 2022CVE publishedPublication date reported by the CVE source.
  2. Dec 6, 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=unspecified <6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=unspecified <6.2

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
2.6Mattermost, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/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.

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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-284Improper Access Control
CWE-863Incorrect Authorization
T1213Data from Information Repositories

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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