CVE-2023-4478 Parameter tampering in the registration resulting in blocked accounts to be created
Attackers can register inactive accounts by tampering with signup parameters, preventing legitimate users from accessing the system without admin intervention.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2023-4478?
CVE-2023-4478 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 25 Aug 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Mattermost fails to restrict which parameters' values it takes from the request during signup allowing an attacker to register users as inactive, thus blocking them from later accessing Mattermost without the system admin activating their accounts.
Weakness: CWE-74
Which versions are affected by CVE-2023-4478?
1 open source package ship an affected version, including mattermost. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mattermost Bitnami | All versions to 8.0.0 | 7.8.9, 7.10.5 |
Products include Mattermost Mattermost Server.
How do I fix CVE-2023-4478?
Upgrade mattermost to a fixed version for your release line: 7.8.9 or 7.10.5.
Is CVE-2023-4478 being exploited?
There is no known exploitation of CVE-2023-4478 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-2023-4478, GHSA-65h8-5q72-mrp3.