CVE-2023-1775 Unsanitized events sent over Websocket to regular users in a High Availability environment
Attackers can view sensitive user and post data via Websocket in High Availability setups due to unsanitized events.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-1775?
CVE-2023-1775 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 31 Mar 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
When running in a High Availability configuration, Mattermost fails to sanitize some of the user_updated and post_deleted events broadcast to all users, leading to disclosure of sensitive information to some of the users with currently connected Websocket clients.
Which versions are affected by CVE-2023-1775?
11 open source packages ship an affected version, including github.com/mattermost/mattermost-server, mattermost and github.com/mattermost/mattermost-server/v5. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/mattermost/mattermost-server Go | From 3.3.0 | 7.1.6 |
github.com/mattermost/mattermost-server Go | From 3.3.0 | 7.1.6 |
github.com/mattermost/mattermost-server Go | From 7.1.0 | 7.1.6 |
github.com/mattermost/mattermost-server Go | From 7.1.0 | 7.1.6 |
github.com/mattermost/mattermost-server Go | From 7.7.0 | 7.7.2 |
github.com/mattermost/mattermost-server Go | From 7.7.0 | 7.7.2 |
5 more packages
mattermost Bitnami | All versions to 7.7.1 | 7.1.6 |
github.com/mattermost/mattermost-server/v5 Go | From 5.0.0 | 7.1.6 |
github.com/mattermost/mattermost-server/v5 Go | From 5.0.0 | 7.1.6 |
github.com/mattermost/mattermost-server/v6 Go | From 6.0.0 | 7.1.6 |
github.com/mattermost/mattermost-server/v6 Go | From 6.0.0 | 7.1.6 |
Products include Mattermost Mattermost Server.
How do I fix CVE-2023-1775?
Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 7.1.6 or 7.7.2.
Is CVE-2023-1775 being exploited?
There is no known exploitation of CVE-2023-1775 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-2023-1775, GHSA-8jhh-3jf2-pfwr.