CVE-2026-93849

EUVD-2026-109937
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
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
MattermostCNA
6.5 MEDIUM
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 39.5%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
mattermostmattermost
11.9.0 ≤
𝑥
≤ 11.9.1
CNA
mattermostmattermost
11.8.0 ≤
𝑥
≤ 11.8.5
CNA
mattermostmattermost
11.7.0 ≤
𝑥
≤ 11.7.10
CNA
mattermostmattermost
11.10.0 ≤
𝑥
≤ 11.10.1
CNA
Common Weakness Enumeration
References
https://mattermost.com/security-updates