CVE-2026-93849
Medium
Description
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 Mattermost fail to apply allocation limits to the byte-string decode paths in its WebSocket msgpack decoder, which allows an authenticated remote attacker to cause excessive server memory allocation via a crafted binary WebSocket frame declaring a Bin32 payload length of up to 4,294,967,295 bytes.. Mattermost Advisory ID: MMSA-2026-00768
SeverityMedium
CVSS6.5
Exploit probability—
Product
Mattermost Server
PublishedOct 26, 2026
First seenOct 26, 2026
Weakness typeCWE-789CWE-789
How to fix
Update
- mattermost mattermost_server11.7.11, 11.8.6, 11.9.2, 11.10.2 or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mattermost mattermost_server | 11.7.0 ≤ v < 11.7.11, 11.8.0 ≤ v < 11.8.6, 11.9.0 ≤ v < 11.9.2, 11.10.0 ≤ v < 11.10.2 | 11.7.11, 11.8.6, 11.9.2, 11.10.2 |
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