Skip to contentMattermost Server vulnerabilities
- mattermost, mattermost server +1 moreMemory Exhaustion via Malicious 7zip File UploadCVE-2026-6340Fix available4.3 Medium
- mattermost, mattermost server +1 moreIncomplete group locking implementationCVE-2026-63414.3 Medium
- mattermost, mattermost server +1 moreGroup prefix matching bypass for subscriptionsCVE-2026-63424.3 Medium
- mattermost, mattermost server +1 moreUnescaped variables during error page compositionCVE-2026-3495Fix available3.8 Low
- mattermost, mattermost server +1 moreInsufficient token rotation validation in remote cluster invite confirmationCVE-2026-4273Fix available3.7 Low
- mattermost, mattermost server +1 moreMattermost fails to enforce create_post permission when editing postsCVE-2026-3637Fix available4.3 Medium
- mattermost, mattermost server +1 moreImproper Input Validation in MS Teams Meetings API HandlerCVE-2026-2325Fix available4.3 Medium
- mattermost, mattermost server +1 moreInsufficient authorization in shared channel membership sync allows remote cluster to remove users from arbitrary channelsCVE-2026-28759Fix available4.3 Medium
- mattermost, mattermost server +1 moreOAuth authorization code client binding not enforced during token redemption in MattermostCVE-2026-6334Fix available3.1 Low
- mattermost, mattermost server +1 morepost edit time limit is not enforced on some post update operationsCVE-2026-4053Fix available3.1 Low
- mattermost, mattermost server +1 moreSVG content served through Mattermost image proxy despite Content-Type restrictions causes client-side denial of serviceCVE-2026-4054Fix available4.3 Medium
- mattermost, mattermost server +1 moreRace Condition in Guest Magic Link Authentication Allows Token ReuseCVE-2026-3590Fix available6.5 Medium
- mattermost, mattermost server +1 moreCSRF Protection Bypass Allows Updating a User's Authentication MethodCVE-2026-28741Fix available6.8 Medium
- mattermost, mattermost server +1 moreConnected Workspaces: Malicious remote server can manipulate arbitrary user's statusCVE-2026-27769Fix available2.7 Low
- mattermost, mattermost server +1 moreUnbounded Request Body Read in MS Teams Plugin {{/lifecycle}} Webhook EndpointCVE-2026-21388Fix available3.7 Low
- mattermost, mattermost server +1 moreArbitrary File Read via Advanced Logging Support PacketCVE-2026-3112Fix available6.8 Medium
- mattermost, mattermost server +1 moreMissing timestamp validation in Zoom webhook handlerCVE-2026-31092.2 Low
- mattermost, mattermost server +1 moreGuest users can view group member IDs without respecting view restrictionsCVE-2026-3115Fix available4.3 Medium
- mattermost, mattermost server +1 moreZip Bomb Denial of Service via Unrestricted Archive DecompressionCVE-2026-3114Fix available6.5 Medium
- mattermost, mattermost server +1 moreImproper Input Validation in Zoom Plugin Webhook HandlerCVE-2026-31164.9 Medium
- mattermost, mattermost server +1 moremmctl export download command doesn’t restrict permissions to created file to file ownerCVE-2026-3113Fix available5.0 Medium
- mattermost, mattermost server +1 moreTerminal Escape Injection in mmctl Report Posts CommandCVE-2026-3108Fix available8.0 High
- mattermost, mattermost server +1 moreInsufficient authorization in shared channel membership sync grants team-level access instead of channel-level accessCVE-2026-4274Fix available5.4 Medium
- mattermost, mattermost server +1 moreCSRF vulnerability in UpdateAccessControlPolicyActiveStatus endpointCVE-2026-27659Fix available4.6 Medium
- mattermost, mattermost server +1 moreDoS via URL Previews Rendering Malicious SVGsCVE-2026-20719Fix available4.3 Medium
- mattermost, mattermost server +1 moreAccount Takeover via Substring Matching in OpenID Connect AuthenticationCVE-2026-27656Fix available5.7 Medium
- mattermost, mattermost server +1 moreDenial of Service via HTTP/2 single packet attack on login endpointCVE-2026-26233Fix available4.3 Medium
- mattermost, mattermost server +1 morePermalink Preview Information Disclosure After Permission RevocationCVE-2026-16294.3 Medium
- mattermost, mattermost server +1 moreTeam Admin Privilege Escalation to Demote Members to GuestCVE-2026-262303.8 Low
- mattermost, mattermost server +1 moreDoS in Calls plugin via malformed msgpack in websocket request.CVE-2026-24545.8 Medium
- mattermost, mattermost server +1 morePermission Bypass in Playbook Run CreationCVE-2026-26304Fix available4.3 Medium
- mattermost, mattermost server +1 moreGuest users can bypass read permissions via search APICVE-2026-24692Fix available4.3 Medium
- mattermost, mattermost server +1 morePassword Change Bypass via Auth Switch EndpointCVE-2026-22545Fix available3.1 Low
- mattermost, mattermost server +1 moreSSRF bypass via IPv4-mapped IPv6 literalsCVE-2026-2455Fix available4.3 Medium
- mattermost, mattermost server +1 morePrivate channel enumeration via /mute slash commandCVE-2026-21386Fix available4.3 Medium
- mattermost, mattermost server +1 moreMemory Exhaustion via Malformed DOC File UploadCVE-2026-25780Fix available4.3 Medium
- mattermost, mattermost server +1 moreGuest user can upload files without permission across teamsCVE-2026-4265Fix available4.3 Medium
- mattermost, mattermost server +1 moreDenial of service via malformed User-Agent header in getBrowserVersionCVE-2026-25783Fix available4.3 Medium
- mattermost, mattermost server +1 moreDoS attack via login attempts with multi-megabyte passwordsCVE-2026-24458Fix available7.5 High
- mattermost, mattermost server +1 moreAdmin RCE via Malicious Plugin Upload on CI Test InstancesCVE-2026-24626.6 Medium
- mattermost, mattermost server +1 moreInformation Disclosure via WebSocket Event When Deleting Unrevealed Burn on Read PostsCVE-2026-2578Fix available4.3 Medium
- mattermost, mattermost server +1 moreMemory Exhaustion via Malformed PSD File UploadCVE-2026-26246Fix available4.3 Medium
- mattermost, mattermost server +1 moreUnauthorized channel enumeration in private teams after member removalCVE-2026-2458Fix available4.3 Medium
- mattermost, mattermost server +1 moreWebSocket Message Spoofing via Permalink Embed ManipulationCVE-2026-2457Fix available4.3 Medium
- mattermost, mattermost server +1 moreMissing authorization check allows unauthorized modification of other users' comments on a boardCVE-2026-2461Public exploitFix available4.3 Medium
- mattermost, mattermost server +1 moreUnauthorized access to invite ID during team creationCVE-2026-2463Fix available4.3 Medium
- mattermost, mattermost server +1 moreDenial of Service via Unbounded Memory Allocation in Integration ActionsCVE-2026-2456Fix available5.3 Medium
- mattermost, mattermost server +1 moreTeam Admin Bypass of Invite Permissions via allow_open_invite FieldCVE-2025-14573Fix available3.8 Low
- mattermost, mattermost server +1 moreInformation disclosure via channel mentions in postsCVE-2025-14350Fix available4.3 Medium
- mattermost, mattermost server +1 moreUser profile update exposes password hash and MFA secretsCVE-2025-13821Fix available5.7 Medium
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