Mattermost: Authenticated DoS through failure to prevent rendering of external SVGs on link embeds

GHSA-86vc-mg26-fj6x · CVE-2026-20719 · GO-2026-5245

Published Mar 25, 2026 · Modified Jun 25, 2026

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

References

ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-20719
PACKAGE https://github.com/mattermost/mattermost
WEB https://mattermost.com/security-updates

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