# Mattermost vulnerabilities Source: https://junglewise.ai/threats/technologies/mattermost Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats Updated: 12 November 2026, 03:07 UTC. Rebuilt every hour. Data: https://junglewise.ai/threats/technologies/mattermost.json License: CC BY 4.0 with a link back Junglewise Threat Intelligence has tracked 9 vulnerabilities in Mattermost: 0 in the last 7 days and 2 in the last 90 days, 0 of them critical and 0 exploited in the wild. The most recent, CVE-2026-14344, was published on 14 September 2026. Nothing in the last four weeks, down from 1 vulnerability in the four before. ## Counts - Last 7 days: 0 - Last 30 days: 0 - Last 90 days: 2 - All time: 9 (0 critical, 0 exploited in the wild) ## About Mattermost Mattermost is an open-source, self-hosted online chat service with file sharing, search, and integrations. ## Latest Mattermost vulnerabilities - [CVE-2026-14344: Mattermost permission bypass in board creation](https://junglewise.ai/threats/cve-2026-14344-mattermost-permission-bypass-in-board-creation) (medium, CVSS 4.3, published 14 Sep 2026) - [CVE-2026-9816: Mattermost privilege escalation via BoardMember.Scheme validation bypass](https://junglewise.ai/threats/cve-2026-9816-mattermost-privilege-escalation-via-boardmember-scheme-validation) (high, CVSS 8.3, published 17 Aug 2026) - [CVE-2026-7521: Mattermost path traversal in file deletion endpoint](https://junglewise.ai/threats/cve-2026-7521-mattermost-path-traversal-in-file-deletion-endpoint) (medium, CVSS 5.5, published 28 Jul 2026) - [CVE-2026-10600: Mattermost resource exhaustion in document content extraction](https://junglewise.ai/threats/cve-2026-10600-mattermost-resource-exhaustion-in-document-content-extraction) (medium, CVSS 4.3, published 27 Jul 2026) - [CVE-2026-6541: Mattermost authorization bypass in Playbook metric configuration](https://junglewise.ai/threats/cve-2026-6541-mattermost-authorization-bypass-in-playbook-metric-configuration) (medium, CVSS 4.3, published 13 Jul 2026) - [CVE-2026-6850: Mattermost ReDoS in client-side markdown parser](https://junglewise.ai/threats/cve-2026-6850-mattermost-redos-in-client-side-markdown-parser) (medium, CVSS 6.5, published 13 Jul 2026) - [CVE-2026-9162: Mattermost insufficient session expiration in WebSocket connections](https://junglewise.ai/threats/cve-2026-9162-mattermost-insufficient-session-expiration-in-websocket) (medium, CVSS 4.3, published 22 Jun 2026) - [CVE-2026-6673: Mattermost authentication bypass in Atlassian Connect callback](https://junglewise.ai/threats/cve-2026-6673-mattermost-authentication-bypass-in-atlassian-connect-callback) (medium, CVSS 6.4, published 22 Jun 2026) - [CVE-2026-5139: Mattermost missing authorization in GitLab connect command](https://junglewise.ai/threats/cve-2026-5139-mattermost-missing-authorization-in-gitlab-connect-command) (medium, CVSS 5.4, published 22 Jun 2026) ## Most severe Mattermost vulnerabilities - [CVE-2026-9816: Mattermost privilege escalation via BoardMember.Scheme validation bypass](https://junglewise.ai/threats/cve-2026-9816-mattermost-privilege-escalation-via-boardmember-scheme-validation) (high, CVSS 8.3, published 17 Aug 2026) - [CVE-2026-6850: Mattermost ReDoS in client-side markdown parser](https://junglewise.ai/threats/cve-2026-6850-mattermost-redos-in-client-side-markdown-parser) (medium, CVSS 6.5, published 13 Jul 2026) - [CVE-2026-6673: Mattermost authentication bypass in Atlassian Connect callback](https://junglewise.ai/threats/cve-2026-6673-mattermost-authentication-bypass-in-atlassian-connect-callback) (medium, CVSS 6.4, published 22 Jun 2026) - [CVE-2026-7521: Mattermost path traversal in file deletion endpoint](https://junglewise.ai/threats/cve-2026-7521-mattermost-path-traversal-in-file-deletion-endpoint) (medium, CVSS 5.5, published 28 Jul 2026) - [CVE-2026-5139: Mattermost missing authorization in GitLab connect command](https://junglewise.ai/threats/cve-2026-5139-mattermost-missing-authorization-in-gitlab-connect-command) (medium, CVSS 5.4, published 22 Jun 2026) - [CVE-2026-9162: Mattermost insufficient session expiration in WebSocket connections](https://junglewise.ai/threats/cve-2026-9162-mattermost-insufficient-session-expiration-in-websocket) (medium, CVSS 4.3, published 22 Jun 2026) - [CVE-2026-14344: Mattermost permission bypass in board creation](https://junglewise.ai/threats/cve-2026-14344-mattermost-permission-bypass-in-board-creation) (medium, CVSS 4.3, published 14 Sep 2026) - [CVE-2026-10600: Mattermost resource exhaustion in document content extraction](https://junglewise.ai/threats/cve-2026-10600-mattermost-resource-exhaustion-in-document-content-extraction) (medium, CVSS 4.3, published 27 Jul 2026) - [CVE-2026-6541: Mattermost authorization bypass in Playbook metric configuration](https://junglewise.ai/threats/cve-2026-6541-mattermost-authorization-bypass-in-playbook-metric-configuration) (medium, CVSS 4.3, published 13 Jul 2026) ## Vulnerabilities per week Nothing in the last four weeks, down from 1 vulnerability in the four before. | Week of | Vulns | Critical | Exploited | | --- | --- | --- | --- | | 17 Aug 2026 | 1 | 0 | 0 | | 24 Aug 2026 | 0 | 0 | 0 | | 31 Aug 2026 | 0 | 0 | 0 | | 7 Sep 2026 | 0 | 0 | 0 | | 14 Sep 2026 | 1 | 0 | 0 | | 21 Sep 2026 | 0 | 0 | 0 | | 28 Sep 2026 | 0 | 0 | 0 | | 5 Oct 2026 | 0 | 0 | 0 | | 12 Oct 2026 | 0 | 0 | 0 | | 19 Oct 2026 | 0 | 0 | 0 | | 26 Oct 2026 | 0 | 0 | 0 | | 2 Nov 2026 | 0 | 0 | 0 | | 9 Nov 2026 | 0 | 0 | 0 | ## Other Mattermost technologies - [Mattermost Server](https://junglewise.ai/threats/technologies/server-public): 111 vulnerabilities - [Mattermost Desktop App](https://junglewise.ai/threats/technologies/desktop-app): 14 vulnerabilities - [Mattermost Plugins](https://junglewise.ai/threats/technologies/mattermost-plugins): 5 vulnerabilities - [Mattermost GitHub Plugin for Mattermost](https://junglewise.ai/threats/technologies/github-plugin): 3 vulnerabilities ## Sources NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "Mattermost vulnerabilities", https://junglewise.ai/threats/technologies/mattermost, 12 November 2026.