Technology · Mattermost
Mattermost Server vulnerabilities
Updated . Rebuilt every hour.
Junglewise Threat Intelligence has tracked 72 vulnerabilities in Mattermost Server: 3 in the last 7 days and 25 in the last 90 days, 0 of them critical and 0 exploited in the wild. The most recent, CVE-2026-96260, was published on 22 September 2026.
- Last 7 days
- 3
- Last 90 days
- 25
- Critical, all time
- 0
- Exploited in the wild
- 0
About Mattermost Server
Server Public is a library containing shared components and utilities for the Mattermost server.
Latest Mattermost Server vulnerabilities
- CVE-2026-96260: Mattermost memory exhaustion in CSRF validation for plugin endpointsmediumCVSS 6.5EPSS 0.4%
- CVE-2026-96259: Mattermost internal-connection filter bypass in OAuth endpointsmediumCVSS 5.5EPSS 0.3%
- CVE-2026-95666: Mattermost denial of service via unbounded post ID arraymediumCVSS 4.3EPSS 0.4%
- CVE-2026-91181: Mattermost information disclosure in data retention teams endpointmediumCVSS 6.5EPSS 0.4%
- CVE-2026-12985: Mattermost OAuth redirect URI validation bypassmediumCVSS 6.8EPSS 0.3%
- CVE-2026-86349: Mattermost Markdown parser denial of servicemediumCVSS 4.3EPSS 0.4%
- CVE-2026-86348: Mattermost denial of service via handler panic in post-action requestmediumCVSS 4.3EPSS 0.4%
- CVE-2026-82920: Mattermost authorization bypass in access control policy endpointmediumCVSS 5.5EPSS 0.3%
- CVE-2026-8821: Mattermost authorization bypass in playbook creationhighCVSS 7.1EPSS 0.3%
- CVE-2026-5132: Mattermost SDP message decompression denial of servicemediumCVSS 6.5EPSS 0.4%
- CVE-2026-14259: Mattermost board creation permissions bypass on archive importmediumCVSS 4.3EPSS 0.1%
- CVE-2026-12882: Mattermost ReDoS in Markdown autolink parsingmediumCVSS 4.3EPSS 0.2%
- CVE-2026-11993: Mattermost file upload goroutine exhaustion denial of servicemediumCVSS 4.3EPSS 0.2%
- CVE-2026-10556: Mattermost Microsoft Calendar plugin denial of service via webhook validation bypassmediumCVSS 5.3EPSS 0.3%
- CVE-2026-10542: Mattermost authorization bypass in channel action updatemediumCVSS 5EPSS 0.1%
- CVE-2026-9859: Mattermost privilege escalation in board channel reassignmentmediumCVSS 6.5EPSS 0.3%
- CVE-2026-10819: Mattermost denial of service via animated GIF emoji uploadsmediumCVSS 6.5
- CVE-2026-9824: Mattermost missing authorization in share-channel autocomplete handlermediumCVSS 4.3
- CVE-2026-9820: Mattermost information disclosure in scheme teams API endpointlowCVSS 3.8
- CVE-2026-9708: Mattermost authorization bypass in incoming webhooksmediumCVSS 4.9
- CVE-2026-9597: Mattermost authentication bypass for deactivated guest accounts via magic-linkmediumCVSS 5.4
- CVE-2026-9571: Mattermost Server OAuth token invalidation failure on account deactivationmediumCVSS 5.9
- CVE-2026-10106: Mattermost incorrect authorization in interactive post actionsmediumCVSS 6.5
- CVE-2026-10103: Mattermost Server authorization bypass in shared channel syncmediumCVSS 4.3
- CVE-2026-10085: Mattermost authorization bypass in channel patch APImediumCVSS 5.4
Most severe Mattermost Server vulnerabilities
Exploited in the wild first, then by severity and CVSS score.
- CVE-2026-7387: Mattermost privilege escalation in group syncable link and patch endpointshighCVSS 8.8EPSS 0.4%
- CVE-2026-6346: Mattermost sensitive information disclosure in support packet generationhighCVSS 8.7EPSS 0.4%
- CVE-2026-4858: Mattermost path traversal in integration action URLhighCVSS 8EPSS 0.4%
- CVE-2026-6961: Mattermost path traversal in shared channel file synchighCVSS 7.6EPSS 0.4%
- CVE-2026-6347: Mattermost Calls plugin information disclosure in support packetshighCVSS 7.6EPSS 0.4%
- CVE-2026-5740: Mattermost Server denial of service via msgpack WebSocket frameshighCVSS 7.5EPSS 0.6%
- CVE-2026-5308: Mattermost denial of service in plugin HTTP endpointshighCVSS 7.5EPSS 0.4%
- CVE-2026-8821: Mattermost authorization bypass in playbook creationhighCVSS 7.1EPSS 0.3%
- CVE-2026-3473: Mattermost Server authorization bypass in Boards APIhighCVSS 7.1EPSS 0.3%
- CVE-2026-12985: Mattermost OAuth redirect URI validation bypassmediumCVSS 6.8EPSS 0.3%
Vulnerabilities per week
The last 13 weeks, by the week each vulnerability was published.
| Week of | Bar | Vulns | Critical |
|---|---|---|---|
| 29 Jun 2026 | 0 | 0 | |
| 6 Jul 2026 | 0 | 0 | |
| 13 Jul 2026 | 8 | 0 | |
| 20 Jul 2026 | 0 | 0 | |
| 27 Jul 2026 | 1 | 0 | |
| 3 Aug 2026 | 0 | 0 | |
| 10 Aug 2026 | 0 | 0 | |
| 17 Aug 2026 | 1 | 0 | |
| 24 Aug 2026 | 0 | 0 | |
| 31 Aug 2026 | 0 | 0 | |
| 7 Sep 2026 | 0 | 0 | |
| 14 Sep 2026 | 12 | 0 | |
| 21 Sep 2026 | 3 | 0 |
How this is built
Junglewise Threat Intelligence collects vulnerabilities from NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories, and matches each one to the technologies and vendors it affects. Dates are the date a vulnerability was published, in UTC.
The pages are rebuilt from the database every hour. Frozen weekly and monthly reports never change once published, so they can be cited.
Use this data
The same data is at https://junglewise.ai/threats/technologies/server-public.json, for scripts and language models. It is free to reuse under CC BY 4.0 with a link back to this page.
Cite as: Junglewise Threat Intelligence, "Mattermost Server vulnerabilities", https://junglewise.ai/threats/technologies/server-public, 26 September 2026.