CVE-2026-8823Low· 3.8▾ SunlitMattermost has an Incorrect Authorization issue
▾ Sunlit zone — Low / medium · no exploitation signal
impact 20.9 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Sep 22.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
Last analysed / modified upstream
0.3%
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
github.com/mattermost/mattermost-server = 11.7.0github.com/mattermost/mattermost-server >= 10.11.0, < 10.11.18github.com/mattermost/mattermost/server/v8 < 8.0.0-20260518160100-9bd77d3fc4d2Upgrade to a patched release:
github.com/mattermost/mattermost-server 11.7.1github.com/mattermost/mattermost-server 10.11.18github.com/mattermost/mattermost/server/v8 8.0.0-20260518160100-9bd77d3fc4d2Connected by shared product, vendor, weakness, or advisory.
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