CVE-2026-8823
published 2026-06-22CVE-2026-8823: Mattermost 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…
PriorityP419low3.8CVSS 3.1
AVNACLPRHUINSUCNILAL
EPSS
0.32%
24.5th percentile
Mattermost 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
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| github.com | mattermost_mattermost-server | >= 10.11.0 < 10.11.18 | 10.11.18 |
| github.com | mattermost_mattermost-server | >= 11.7.0 < 11.7.1 | 11.7.1 |
| github.com | mattermost_mattermost_server_v8 | >= 0 < 8.0.0-20260518160100-9bd77d3fc4d2 | 8.0.0-20260518160100-9bd77d3fc4d2 |
| mattermost | mattermost | 10.11.0 – 10.11.17 | — |
| mattermost | mattermost | 11.7.0 – 11.7.0 | — |
| mattermost | mattermost_server | >= 10.11.0 < 10.11.18 | 10.11.18 |
| mattermost | mattermost_server | >= 11.7.0 < 11.7.1 | 11.7.1 |
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VulDB
Mattermost up to 10.11.17/11.7.0/11.7.x Standard demote-user API authorization
vuldb·2026-06-22·CVSS 3.8
CVE-2026-8823 [LOW] Mattermost up to 10.11.17/11.7.0/11.7.x Standard demote-user API authorization
A vulnerability was found in Mattermost up to 10.11.17/11.7.0/11.7.x. It has been classified as problematic. This vulnerability affects unknown code of the component Standard demote-user API. This manipulation causes incorrect authorization.
This vulnerability is tracked as CVE-2026-8823. The attack is possible to be carried out remotely. No exploit exists.
Upgrading the affected component is recommended.
GHSA
Mattermost has an Incorrect Authorization issue
ghsa·2026-06-22
CVE-2026-8823 [LOW] CWE-863 Mattermost has an Incorrect Authorization issue
Mattermost has an Incorrect Authorization issue
Mattermost 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
GHSA
Mattermost 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
ghsa_unreviewed·2026-06-22
CVE-2026-8823 [LOW] CWE-863 Mattermost 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
Mattermost 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
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-06-22
Published