CVE-2026-20719

DoS via URL Previews Rendering Malicious SVGs

CVSS 4.3 MEDIUMEPSS 0.4%CWE-754

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

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected products

Mattermost · Mattermost

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References

https://mattermost.com/security-updates