CVE-2020-14450 Denial of service in n/a
Attackers can cause client-side denial of service in Mattermost Server via the markdown renderer, requiring an upgrade to resolve.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-14450?
CVE-2020-14450 is a high-severity denial of service 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 5.22.0. The markdown renderer allows attackers to cause a denial of service (client-side), aka MMSA-2020-0017.
Which versions are affected by CVE-2020-14450?
1 open source package ship an affected version, including mattermost. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mattermost Bitnami | All versions | 5.22.0 |
Products include Mattermost Mattermost Server.
How do I fix CVE-2020-14450?
Upgrade mattermost to 5.22.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2020-14450 being exploited?
There is no known exploitation of CVE-2020-14450 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 BIT-mattermost-2020-14450, GHSA-c5gw-q265-vfqw.