Bug 2458663 (CVE-2026-3590) - CVE-2026-3590 mattermost: race condition in guest magic link authentication allows token reuse
Summary: CVE-2026-3590 mattermost: race condition in guest magic link authentication a...
Keywords:
Status: NEW
Alias: CVE-2026-3590
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2458726 2458727
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-15 12:01 UTC by OSIDB Bzimport
Modified: 2026-04-17 17:52 UTC (History)
0 users

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Description OSIDB Bzimport 2026-04-15 12:01:14 UTC 
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
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