How severe is CVE-2023-1775?

CVE-2023-1775 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2023-1775 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-1775?

CVE-2023-1775 primarily affects Mattermost Mattermost Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-1775?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2023-1775 published?

CVE-2023-1775 was published on 2023-03-31 and last updated on 2026-06-17.

CVE-2023-1775

CVE-2023-1775 is a medium-severity vulnerability in Mattermost Mattermost Server with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-668.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-668
Affected product: Mattermost Mattermost Server
Published: 2023-03-31
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2023-1775?: 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.
How severe is CVE-2023-1775?: CVE-2023-1775 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2023-1775 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-1775?: CVE-2023-1775 primarily affects Mattermost Mattermost Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-1775?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-1775 published?: CVE-2023-1775 was published on 2023-03-31 and last updated on 2026-06-17.

References

https://mattermost.com/security-updates/

Affected products (2)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_server:7.7.1:*:*:*:*:*:*:*

More vulnerabilities in Mattermost Mattermost Server

CVE-2025-12421 — Critical (CVSS 9.9): Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to to verify that…
CVE-2025-12419 — Critical (CVSS 9.9): Mattermost versions 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12, 11.0.x <= 11.0.3 fail to properly…
CVE-2025-4981 — Critical (CVSS 9.9): Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to…
CVE-2025-25279 — Critical (CVSS 9.9): Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate…
CVE-2025-20051 — Critical (CVSS 9.9): Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate…
CVE-2017-18920 — Critical (CVSS 9.8): An issue was discovered in Mattermost Server before 3.6.2. The WebSocket feature does not follow the Same Origin Policy.

All CVEs affecting Mattermost Mattermost Server →

Other CWE-668 (Exposure of Resource to Wrong Sphere) vulnerabilities

CVE-2025-2857 — Critical (CVSS 10.0): Following the recent Chrome sandbox escape (CVE-2025-2783), various Firefox developers identified a similar pattern in…
CVE-2019-8779 — Critical (CVSS 10.0): A logic issue applied the incorrect restrictions. This issue was addressed by updating the logic to apply the correct…
CVE-2012-1846 — Critical (CVSS 10.0): Google Chrome 17.0.963.66 and earlier allows remote attackers to bypass the sandbox protection mechanism by leveraging…
CVE-2022-43684 — Critical (CVSS 9.9): ServiceNow has released patches and an upgrade that address an Access Control List (ACL) bypass issue in ServiceNow…
CVE-2022-24900 — Critical (CVSS 9.9): Piano LED Visualizer is software that allows LED lights to light up as a person plays a piano connected to a computer.…
CVE-2019-16541 — Critical (CVSS 9.9): Jenkins JIRA Plugin 3.0.10 and earlier does not declare the correct (folder) scope for per-folder Jira site…

Browse all CWE-668 (Exposure of Resource to Wrong Sphere) vulnerabilities →