Unsanitized events sent over Websocket to regular users in a High Availability environment
Priority LOW 30CWE-200Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-200.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00546 46th percentileScored 2026-11-07
Fix Fixed Mattermost (Mattermost): 7.8.0, 7.7.2, 7.1.6github.com/mattermost/mattermost-server (Go): 7.1.6, 7.7.2+2 more products
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Mattermost | Mattermost | 3.3.0 – 7.7.1; 3.3.0 – 7.1.5; 3.3.0 to before 7.8.0 | 7.8.0, 7.7.2, 7.1.6 | Patch available | CNA |
| — | github.com/mattermost/mattermost-server (Go) | 3.3.0 to before 7.1.6 | 7.1.6 | Patch available | GHSA-8jhh-3jf2-pfwr |
| — | github.com/mattermost/mattermost-server (Go) | 7.7.0 to before 7.7.2 | 7.7.2 | Patch available | GHSA-8jhh-3jf2-pfwr |
| — | github.com/mattermost/mattermost-server (Go) | 7.1.0 to before 7.1.6 | 7.1.6 | Patch available | GHSA-8jhh-3jf2-pfwr |
| — | github.com/mattermost/mattermost-server/v5 (Go) | 5.0.0 to before 7.1.6 | 7.1.6 | Patch available | GHSA-8jhh-3jf2-pfwr |
| — | github.com/mattermost/mattermost-server/v6 (Go) | 6.0.0 to before 7.1.6 | 7.1.6 | Patch available | GHSA-8jhh-3jf2-pfwr |
- Mattermost VendorMattermost Affected 3.3.0 – 7.7.1; 3.3.0 – 7.1.5; 3.3.0 to before 7.8.0 Fixed in 7.8.0, 7.7.2, 7.1.6 Patch available CNA
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 3.3.0 to before 7.1.6 Fixed in 7.1.6 Patch available GHSA-8jhh-3jf2-pfwr
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 7.7.0 to before 7.7.2 Fixed in 7.7.2 Patch available GHSA-8jhh-3jf2-pfwr
- github.com/mattermost/mattermost-server (Go) Vendor— Affected 7.1.0 to before 7.1.6 Fixed in 7.1.6 Patch available GHSA-8jhh-3jf2-pfwr
- github.com/mattermost/mattermost-server/v5 (Go) Vendor— Affected 5.0.0 to before 7.1.6 Fixed in 7.1.6 Patch available GHSA-8jhh-3jf2-pfwr
- github.com/mattermost/mattermost-server/v6 (Go) Vendor— Affected 6.0.0 to before 7.1.6 Fixed in 7.1.6 Patch available GHSA-8jhh-3jf2-pfwr
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | before 7.1.6 | Vulnerable | Mattermost |
| cpe:2.3:a:mattermost:mattermost_server:7.7.1:*:*:*:*:*:*:* | 7.7.1 | Vulnerable | Mattermost |
- cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* Versions before 7.1.6 Vulnerable ·Mattermost
- cpe:2.3:a:mattermost:mattermost_server:7.7.1:*:*:*:*:*:*:* Versions 7.7.1 Vulnerable ·Mattermost
Remediation
- Fix · CNA Mattermost (Mattermost) Fixed in 7.8.0, 7.7.2, 7.1.6
- Fix · GHSA-8jhh-3jf2-pfwr github.com/mattermost/mattermost-server (Go) Fixed in 7.1.6 Advisory →
- Fix · GHSA-8jhh-3jf2-pfwr github.com/mattermost/mattermost-server (Go) Fixed in 7.7.2 Advisory →
- Fix · GHSA-8jhh-3jf2-pfwr github.com/mattermost/mattermost-server (Go) Fixed in 7.1.6 Advisory →
- Fix · GHSA-8jhh-3jf2-pfwr github.com/mattermost/mattermost-server/v5 (Go) Fixed in 7.1.6 Advisory →
- Fix · GHSA-8jhh-3jf2-pfwr github.com/mattermost/mattermost-server/v6 (Go) Fixed in 7.1.6 Advisory →
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Mattermost 7.8.0
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2023-01669 Stored XSS via SVG attachment on BoardsPriority LOW 34
- TI-2023-01667 Unauthorized email invite to a private channelPriority LOW 24
Timeline
- 2026-10-02 Threatist record created from CVE-2023-1775
- 2026-10-03 Alias added: GHSA-8jhh-3jf2-pfwr
References
More Mattermost Server vulnerabilities
- TI-2025-18933 Arbitrary file read in Mattermost Boards via import & export board archive CVSS 3.1CRITICAL 9.9
- TI-2025-04465 Path Traversal Leading to RCE by Any Authenticated Mattermost User CVSS 3.1CRITICAL 9.9
- TI-2017-14068 An issue was discovered in Mattermost Server before 3.6.2. CVSS 3.1CRITICAL 9.8
- TI-2017-14060 An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. CVSS 3.1CRITICAL 9.8
- TI-2017-14048 An issue was discovered in Mattermost Server before 4.1.0, 4.0.4, and 3.10.3. CVSS 3.1CRITICAL 9.8
- TI-2025-14360 Arbitrary file read via block duplication in Mattermost Boards CVSS 3.1CRITICAL 9.9
Sources
- CVE-2023-1775 · CVE Program
- CVE-2023-1775 · NVD
- FIRST EPSS
- GHSA-8jhh-3jf2-pfwr · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences