CVE-2018-21248 Information disclosure in n/a
Mattermost Server mishandles superfluous authentication credentials, potentially leading to information disclosure.
- 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-2018-21248?
CVE-2018-21248 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 5.4.0. It mishandles possession of superfluous authentication credentials.
Weakness: CWE-522
Which versions are affected by CVE-2018-21248?
It affects 1 product.
Products include Mattermost Mattermost Server.
How do I fix CVE-2018-21248?
No fix has been published for CVE-2018-21248 yet. Limit exposure of the affected software until one is available.
Is CVE-2018-21248 being exploited?
There is no known exploitation of CVE-2018-21248 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-xppr-f495-xp3j.