CVE-2025-20621

Mattermost versions 10.2.x <= 10.2.0, 9.11.x <= 9.11.5, 10.0.x <= 10.0.3, 10.1.x <= 10.1.3 fail to properly handle posts with attachments containing fields that cannot be cast to a String, which allows an attacker to cause the webapp to crash via creating and sending such a post to a channel.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTNIST
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
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
CISA-ADPADP
---
---
Base Score
CVSS 3.x
EPSS Score
Percentile: 50%
VendorProductVersion
mattermostmattermost_server
9.11.0 ≤
𝑥
< 9.11.6
mattermostmattermost_server
10.0.0 ≤
𝑥
< 10.0.4
mattermostmattermost_server
10.1.0 ≤
𝑥
< 10.1.4
mattermostmattermost_server
10.2.0
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://mattermost.com/security-updates