User Manager can demote bot accounts to guest without bot-management permission

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-8823
StatePUBLISHED
AssignerMattermost
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-22 16:16:42 UTC
Updated2026-06-22 18:29:30 UTC
DescriptionMattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669

Risk And Classification

Primary CVSS: v3.1 3.8 LOW from [email protected]

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L

Problem Types: CWE-863 | CWE-863 CWE-863: Incorrect Authorization

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary3.8LOWCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L
3.1CNACVSS3.8LOWCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mattermost Mattermost affected 11.7.0 11.7.0 semver Not specified
CNA Mattermost Mattermost affected 10.11.0 10.11.17 semver Not specified
CNA Mattermost Mattermost unaffected 11.8.0 Not specified
CNA Mattermost Mattermost unaffected 11.7.1 Not specified
CNA Mattermost Mattermost unaffected 10.11.18 Not specified

References

ReferenceSourceLinkTags
mattermost.com/security-updates [email protected] mattermost.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Edgar Bellot Micó (en)

Additional Advisory Data

Solutions

CNA: Update Mattermost to versions 11.8.0, 11.7.1, 10.11.18 or higher.

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