CVE-2018-21261 Information disclosure in n/a
Mattermost Server exposed team invite IDs in emails, allowing attackers to gain excessive invitation privileges and bypass intended access controls.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2018-21261?
CVE-2018-21261 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 19 Jun 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An issue was discovered in Mattermost Server before 4.8.1, 4.7.4, and 4.6.3. An e-mail invite accidentally included the team invite_id, which leads to unintended excessive invitation privileges.
Weakness: CWE-732
Which versions are affected by CVE-2018-21261?
It affects 1 product.
Products include Mattermost Mattermost Server.
How do I fix CVE-2018-21261?
No fix has been published for CVE-2018-21261 yet. Limit exposure of the affected software until one is available.
Is CVE-2018-21261 being exploited?
There is no known exploitation of CVE-2018-21261 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-8wj9-f85x-v82p.