CVE-2026-10819
Medium
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
SeverityMedium
CVSS6.5
Exploit probability—
Product
Mattermost Server
PublishedJul 27, 2026
First seenJul 27, 2026
Weakness typeCWE-409CWE-409
How to fix
Update
- mattermost mattermost_server10.11.21, 11.6.6, 11.7.5, 11.8.2 or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mattermost mattermost_server | 10.11.0 ≤ v < 10.11.21, 11.6.0 ≤ v < 11.6.6, 11.7.0 ≤ v < 11.7.5, 11.8.0 ≤ v < 11.8.2 | 10.11.21, 11.6.6, 11.7.5, 11.8.2 |
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