6.5
Medium
CVE-2026-93849 Mattermost versions…
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
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Mattermost 11.11 | earliest → < 11.11.0 | 11.11.0 |
| Mattermost 11.10 | 11.10.0 → 11.10.1 | 11.10.2 |
| Mattermost 11.9 | 11.9.0 → 11.9.1 | 11.9.2 |
| Mattermost 11.8 | 11.8.0 → 11.8.5 | 11.8.6 |
| Mattermost 11.7 | 11.7.0 → 11.7.10 | 11.7.11 |