Is CVE-2026-10819 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-10819?

CVE-2026-10819 has a CVSS v3 severity of MEDIUM (6.5).

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CVE-2026-10819

Description

Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number of frames and enforce the file size cap on animated GIF uploads, which allows an authenticated attacker to cause a denial of service via a crafted animated GIF uploaded as a custom emoji.. Mattermost Advisory ID: MMSA-2026-00695