Auth bypass in Mattermost Server

CVE-2018-21251

An issue was discovered in Mattermost Server before 5.2 and 5.1.1. Authorization could be bypassed if the channel name were not the same in the params and the body.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.012 (66.9th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 67th percentile — 66.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2018-21251: held from 0.012 to 0.012.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2018-21251?
CVE-2018-21251 is a critical-severity vulnerability in Mattermost Server, classified under Missing Authorization. CVSS score: 9.8/10. Published 2020-06-19.
How severe is CVE-2018-21251?
Critical severity. CVSS v3 base score is 9.8 out of 10.