Vulnerability Details CVE-2026-3590
Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 9.5%
CVSS Severity
CVSS v3 Score 6.5
References
Products affected by CVE-2026-3590
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cpe:2.3:a:mattermost:mattermost_server:10.11.0
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cpe:2.3:a:mattermost:mattermost_server:10.11.1
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cpe:2.3:a:mattermost:mattermost_server:10.11.10
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cpe:2.3:a:mattermost:mattermost_server:10.11.11
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cpe:2.3:a:mattermost:mattermost_server:10.11.12
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cpe:2.3:a:mattermost:mattermost_server:10.11.2
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cpe:2.3:a:mattermost:mattermost_server:10.11.3
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cpe:2.3:a:mattermost:mattermost_server:10.11.4
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cpe:2.3:a:mattermost:mattermost_server:10.11.5
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cpe:2.3:a:mattermost:mattermost_server:10.11.6
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cpe:2.3:a:mattermost:mattermost_server:10.11.7
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cpe:2.3:a:mattermost:mattermost_server:10.11.8
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cpe:2.3:a:mattermost:mattermost_server:10.11.9
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cpe:2.3:a:mattermost:mattermost_server:11.3.0
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cpe:2.3:a:mattermost:mattermost_server:11.3.1
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cpe:2.3:a:mattermost:mattermost_server:11.3.2
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cpe:2.3:a:mattermost:mattermost_server:11.4.0
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cpe:2.3:a:mattermost:mattermost_server:11.4.1
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cpe:2.3:a:mattermost:mattermost_server:11.4.2
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cpe:2.3:a:mattermost:mattermost_server:11.5.0