CVE-2026-20719
Medium
Description
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to prevent rendering of external SVGs on link embeds which allows unauthenticated users to crash the Mattermost webapp and desktop app via creating an issue or PR on GitHub.. Mattermost Advisory ID: MMSA-2026-00595
SeverityMedium
CVSS4.3
Exploit probability—
Product
Mattermost Server
PublishedMar 25, 2026
First seenMar 25, 2026
Weakness typeCWE-754CWE-754
How to fix
Update
- mattermost mattermost_server10.11.12, 11.2.4, 11.3.2, 11.4.1 or later
- github.com/mattermost/mattermost/server/v811.4.1, 11.3.2, 11.2.4, 8.0.0-20260217110922-b7d4a1f1f59b, 10.11.2 or later
- github.com/mattermost/mattermost-server10.11.2+incompatible, 11.2.4+incompatible, 11.3.2+incompatible, 11.4.1+incompatible or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mattermost mattermost_server | 10.11.0 ≤ v < 10.11.12, 11.2.0 ≤ v < 11.2.4, 11.3.0 ≤ v < 11.3.2, 11.4.0 ≤ v < 11.4.1 | 10.11.12, 11.2.4, 11.3.2, 11.4.1 |
| github.com/mattermost/mattermost/server/v8Go | 11.4.0-rc1 ≤ v < 11.4.1, 11.3.0-rc1 ≤ v < 11.3.2, 11.2.0-rc1 ≤ v < 11.2.4, 8.0.0-20260105080200-d27a2195068d ≤ v < 8.0.0-20260217110922-b7d4a1f1f59b, 10.11.0-rc1 ≤ v < 10.11.2 | 11.4.1, 11.3.2, 11.2.4, 8.0.0-20260217110922-b7d4a1f1f59b, 10.11.2 |
| github.com/mattermost/mattermost-serverGo | 10.11.0-rc1+incompatible ≤ v < 10.11.2+incompatible, 11.2.0-rc1+incompatible ≤ v < 11.2.4+incompatible, 11.3.0-rc1+incompatible ≤ v < 11.3.2+incompatible, 11.4.0-rc1+incompatible ≤ v < 11.4.1+incompatible | 10.11.2+incompatible, 11.2.4+incompatible, 11.3.2+incompatible, 11.4.1+incompatible |
| github.com/mattermost/mattermost-server/v5Go | No range specified | — |
| github.com/mattermost/mattermost-server/v6Go | No range specified | — |
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