CVE-2023-1775
Unsanitized events sent over Websocket to regular users in a High Availability environment
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Unsanitized events sent over Websocket to regular users in a High Availability environment
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.
- Record
CVE-2023-1775- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
EUVDEUVD-2023-0949
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.
- Record
EUVD-2023-0949- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-8jhh-3jf2-pfwr
Mattermost vulnerable to information disclosure
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.
Issue Identifier: MMSA-2023-00138
- Record
GHSA-8jhh-3jf2-pfwr- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-668
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2023-1775- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-200, CWE-668
- Updated
- 2026-11-02
OSV
Unsanitized events sent over Websocket to regular users in a High Availability environment
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.
- Record
CVE-2023-1775- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-200
- Updated
- 2026-11-02
OSVGHSA-8jhh-3jf2-pfwr
Mattermost vulnerable to information disclosure
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.
Issue Identifier: MMSA-2023-00138
- Record
GHSA-8jhh-3jf2-pfwr- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-668
- Updated
- 2026-11-02
OSVBIT-mattermost-2023-1775 No score
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.
- Record
BIT-mattermost-2023-1775- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/mattermost/mattermost-serverGo |
3.3.0 to 4.10.10 | 7.1.6 |
github.com/mattermost/mattermost-serverGo |
7.7.0 to 7.7.1 | 7.7.2 |
github.com/mattermost/mattermost-serverGo |
7.1.0 to 7.1.5 | 7.1.6 |
github.com/mattermost/mattermost-server/v5Go |
5.0.0 to 5.39.3 | 7.1.6 |
github.com/mattermost/mattermost-server/v6Go |
6.0.0 to 6.7.2 | 7.1.6 |
mattermostBitnami |
before 7.1.6, 7.7.1 to 7.7.1 | 7.1.6 |
github.com/mattermost/mattermost-serverGo |
3.3.0 up to 7.1.6 | 7.1.6 |
github.com/mattermost/mattermost-serverGo |
7.7.0 up to 7.7.2 | 7.7.2 |
github.com/mattermost/mattermost-serverGo |
7.1.0 up to 7.1.6 | 7.1.6 |
github.com/mattermost/mattermost-server/v5Go |
5.0.0 up to 7.1.6 | 7.1.6 |
github.com/mattermost/mattermost-server/v6Go |
6.0.0 up to 7.1.6 | 7.1.6 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-1775 is a medium vulnerability (CVSS 4.3) in Mattermost, published March 31, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.55%, the 46th percentile. Fixed in github.com/mattermost/mattermost-server 7.1.6.