CVE-2025-20621 — Improper Validation of Specified Type of Input in Mattermost Mattermost-server

CWE-1287 — Improper Validation of Specified Type of Input5 documents4 sources
Severity
7.5HIGHNVD
CNA6.5
EPSS
0.4%
top 39.92%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
4
Github.com Mattermost Mattermost-serverGithub.com Mattermost Mattermost Server V8Mattermost Server+1 more
Timeline
PublishedJan 16
Latest updateJan 17

Description

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitability: 3.9 | Impact: 3.6

Affected Packages4 packages

▶NVDmattermost/mattermost_server9.11.0 — 9.11.6+3
▶Gogithub.com/mattermost_mattermost-server9.11.0+incompatible — 9.11.6+incompatible+3
▶CVEListV5mattermost/mattermost10.2.0 — 10.2.0+3

🔴Vulnerability Details

4
OSV
Mattermost webapp crash via a crafted post in github.com/mattermost/mattermost-server↗2025-01-17
▶
GHSA
Mattermost webapp crash via a crafted post↗2025-01-16
▶
CVEList
Webapp crash via object that can't be cast to String in Attachment Field↗2025-01-16
▶
OSV
Mattermost webapp crash via a crafted post↗2025-01-16
▶
CVE-2025-20621 — HIGH severity | cvebase