CVE-2018-21260 Information disclosure in n/a
Mattermost Server leaks user privacy data via WebSocket events during user-management operations, requiring an upgrade to secure user information.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2018-21260?
CVE-2018-21260 is a low-severity vulnerability in Mattermost Mattermost Server, published on 19 Jun 2020. An attacker needs administrator access to exploit it, 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. WebSocket events were accidentally sent during certain user-management operations, violating user privacy.
Weakness: CWE-200
Which versions are affected by CVE-2018-21260?
It affects 1 product.
Products include Mattermost Mattermost Server.
How do I fix CVE-2018-21260?
No fix has been published for CVE-2018-21260 yet. Limit exposure of the affected software until one is available.
Is CVE-2018-21260 being exploited?
There is no known exploitation of CVE-2018-21260 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-2294-5jgv-f8mf.