CVE-2026-28741
Medium
Description
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 validate CSRF tokens on an authentication endpoint which allows an attacker to update a user's authentication method via a CSRF attack by tricking a user into visiting a malicious page. Mattermost Advisory ID: MMSA-2026-00625
SeverityMedium
CVSS6.8
Exploit probability—
Product
Mattermost Server
PublishedApr 15, 2026
First seenApr 15, 2026
Weakness typeCWE-352Cross-site request forgery (CSRF)
How to fix
Update
- mattermost mattermost_server10.11.13, 11.3.3, 11.4.3, 11.5.1 or later
- github.com/mattermost/mattermost/server/v88.0.0-20260220133927-c29cf05d40f8, 11.5.0, 11.4.3, 11.3.3 or later
- github.com/mattermost/mattermost-server11.3.3+incompatible, 11.4.3+incompatible, 11.5.0+incompatible or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mattermost mattermost_server | 10.11.0 ≤ v < 10.11.13, 11.3.0 ≤ v < 11.3.3, 11.4.0 ≤ v < 11.4.3, 11.5.0 ≤ v < 11.5.1 | 10.11.13, 11.3.3, 11.4.3, 11.5.1 |
| github.com/mattermost/mattermost/server/v8Go | 8.0.0-20250721062209-4952acea88ce ≤ v < 8.0.0-20260220133927-c29cf05d40f8, 11.5.0-rc1 ≤ v < 11.5.0, 11.4.0-rc1 ≤ v < 11.4.3, 11.3.0-rc1 ≤ v < 11.3.3 | 8.0.0-20260220133927-c29cf05d40f8, 11.5.0, 11.4.3, 11.3.3 |
| github.com/mattermost/mattermost-serverGo | 11.3.0-rc1+incompatible ≤ v < 11.3.3+incompatible, 11.4.0-rc1+incompatible ≤ v < 11.4.3+incompatible, 11.5.0-rc1+incompatible ≤ v < 11.5.0+incompatible | 11.3.3+incompatible, 11.4.3+incompatible, 11.5.0+incompatible |
| github.com/mattermost/mattermost-server/v5Go | No range specified | — |
| github.com/mattermost/mattermost-server/v6Go | No range specified | — |
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