Vulnerability Details CVE-2026-6333
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost Advisory ID: MMSA-2026-00582
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 9.4%
CVSS Severity
CVSS v3 Score 3.5
References
Products affected by CVE-2026-6333
-
cpe:2.3:a:mattermost:mattermost_server:10.11.0
-
cpe:2.3:a:mattermost:mattermost_server:10.11.1
-
cpe:2.3:a:mattermost:mattermost_server:10.11.10
-
cpe:2.3:a:mattermost:mattermost_server:10.11.11
-
cpe:2.3:a:mattermost:mattermost_server:10.11.12
-
cpe:2.3:a:mattermost:mattermost_server:10.11.13
-
cpe:2.3:a:mattermost:mattermost_server:10.11.2
-
cpe:2.3:a:mattermost:mattermost_server:10.11.3
-
cpe:2.3:a:mattermost:mattermost_server:10.11.4
-
cpe:2.3:a:mattermost:mattermost_server:10.11.5
-
cpe:2.3:a:mattermost:mattermost_server:10.11.6
-
cpe:2.3:a:mattermost:mattermost_server:10.11.7
-
cpe:2.3:a:mattermost:mattermost_server:10.11.8
-
cpe:2.3:a:mattermost:mattermost_server:10.11.9
-
cpe:2.3:a:mattermost:mattermost_server:11.5.0
-
cpe:2.3:a:mattermost:mattermost_server:11.5.1