CVE-2017-18889 — Improper Input Validation in Mattermost Mattermost-server

CWE-20 — Improper Input Validation5 documents4 sources
Severity
4.3MEDIUMNVD
EPSS
0.2%
top 54.02%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Github.com Mattermost Mattermost-serverMattermost Server
Timeline
PublishedJun 19
Latest updateDec 15

Description

An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2. An attacker could create fictive system-message posts via webhooks and slash commands, in the v3 or v4 REST API.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:NExploitability: 2.8 | Impact: 1.4

Affected Packages2 packages

▶NVDmattermost/mattermost_server4.2.0 — 4.2.1+2
▶Gogithub.com/mattermost_mattermost-server4.2.0-rc1 — 4.2.1+5

🔴Vulnerability Details

4
OSV
Mattermost Server is vulnerable to webhook and slash command manipulation in github.com/mattermost/mattermost-server↗2025-12-15
▶
OSV
Mattermost Server is vulnerable to webhook and slash command manipulation↗2022-05-24
▶
GHSA
Mattermost Server is vulnerable to webhook and slash command manipulation↗2022-05-24
▶
CVEList
CVE-2017-18889: An issue was discovered in Mattermost Server before 4↗2020-06-19
▶
CVE-2017-18889 — Improper Input Validation | cvebase