CVE-2026-10819
Mattermost Server Denial of Service via Animated GIF Emoji Upload
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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
| CWE | CWE-409 |
| Vendor | mattermost |
| Product | mattermost |
| Published | Jul 27, 2026 |
| Last Updated | Jul 27, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Mattermost / Mattermost
11.6.0 ≤ 11.6.5 10.11.0 ≤ 10.11.20 11.8.0 ≤ 11.8.1 11.7.0 ≤ 11.7.4
Credits
Adam Korczynski