CVE-2019-20886 Privilege escalation in n/a
The first user to register on Mattermost Server may inadvertently gain system administrator privileges, allowing unauthorized administrative control.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2019-20886?
CVE-2019-20886 is a high-severity vulnerability in Mattermost Mattermost Server, published on 19 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An issue was discovered in Mattermost Server before 5.8.0. The first user is sometimes inadvertently a system admin.
Weakness: CWE-269
Which versions are affected by CVE-2019-20886?
It affects 1 product.
Products include Mattermost Mattermost Server.
How do I fix CVE-2019-20886?
No fix has been published for CVE-2019-20886 yet. Limit exposure of the affected software until one is available.
Is CVE-2019-20886 being exploited?
There is no known exploitation of CVE-2019-20886 in the wild and no public exploit code.
Other vulnerabilities in Mattermost Mattermost Server
- CVE-2025-12419 Account takeover on OAuth/OpenID-enabled servers
- CVE-2025-12421 Account Takeover via Code Exchange Endpoint
- CVE-2025-4981 Path Traversal Leading to RCE by Any Authenticated Mattermost User
- CVE-2025-20051 Arbitrary file read via block duplication in Mattermost Boards
- CVE-2025-25279 Arbitrary file read in Mattermost Boards via import & export board archive
Sources
Also known as GHSA-gg2f-8p5w-8x48.