What is CVE-2021-37862?

CVE-2021-37862 is a low-severity vulnerability in Mattermost, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 3.7/10. Published 2021-12-17.

How severe is CVE-2021-37862?

Low severity. CVSS v3 base score is 3.7 out of 10.

Vulnerability in Mattermost

CVE-2021-37862

Mattermost 6.0 and earlier fails to sufficiently validate the email address during registration, which allows attackers to trick users into signing up using attacker-controlled email addresses via crafted invitation token.

Published 2021-12-17 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (49.9th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Mattermost — versions unspecified
Mattermost Server

Weakness classification (CWE)

CWE-754 — Improper Check for Unusual or Exceptional Conditions

References

mattermost.com/security-updates/ (Vendor Advisory)
hackerone.com/reports/1357013 (Permissions Required)

Frequently asked questions

What is CVE-2021-37862?: CVE-2021-37862 is a low-severity vulnerability in Mattermost, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 3.7/10. Published 2021-12-17.
How severe is CVE-2021-37862?: Low severity. CVSS v3 base score is 3.7 out of 10.