Mattermost
by Mattermost
Source repositories
CVEs (595)
| CVE | Vendor / Product | Sev | Risk | CVSS | EPSS | KEV | Published | Description |
|---|---|---|---|---|---|---|---|---|
| CVE-2026-10819 | Med | 0.35 | 6.5 | 0.00 | Jul 27, 2026 | Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number of frames and enforce the file size cap on animated GIF uploads, which allows an authenticated attacker to cause a denial of service via a crafted animated GIF… | ||
| CVE-2026-10106 | Med | 0.35 | 6.5 | 0.00 | Jul 13, 2026 | Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify that the channel referenced in an action cookie matches the channel of the target post, which allows an authenticated user without access to a private channel to trigger interactive post… | ||
| CVE-2026-6673 | Med | 0.35 | 6.4 | 0.00 | Jun 22, 2026 | Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to… | ||
| CVE-2026-6062 | Med | 0.35 | 6.4 | 0.00 | Jun 22, 2026 | Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to… | ||
| CVE-2026-7184 | Med | 0.35 | 6.5 | 0.00 | Jun 12, 2026 | Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows authenticated users with the {{manage_secure_connections}} permission to obtain remote cluster authentication tokens via… | ||
| CVE-2026-4915 | Med | 0.35 | 6.5 | 0.00 | May 25, 2026 | Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to filter nil elements from outgoing webhook attachment payloads before processing, which allows an authenticated user to cause a denial of service (server process termination) via… | ||
| CVE-2026-5755 | Med | 0.35 | 6.5 | 0.00 | May 22, 2026 | Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.2, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a… | ||
| CVE-2026-4635 | Med | 0.35 | 6.5 | 0.00 | May 22, 2026 | Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message… | ||
| CVE-2026-6345 | Med | 0.35 | 6.5 | 0.00 | May 18, 2026 | Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614 | ||
| CVE-2026-5163 | Med | 0.35 | 6.5 | 0.00 | May 18, 2026 | Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to read the content of threads in private channels and direct messages they do not have access to via a crafted request to… | ||
| CVE-2026-3590 | Med | 0.35 | 6.5 | 0.00 | Apr 15, 2026 | Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated… | ||
| CVE-2026-3114 | Med | 0.35 | 6.5 | 0.00 | Mar 26, 2026 | Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to validate decompressed archive entry sizes during file extraction which allows authenticated users with file upload permissions to cause a denial of service via crafted zip… | ||
| CVE-2025-12689 | Med | 0.35 | 6.5 | 0.00 | Dec 17, 2025 | Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, 10.11.x <= 10.11.6 fail to check WebSocket request field for proper UTF-8 format, which allows attacker to crash Calls plug-in via sending malformed request. | ||
| CVE-2025-55070 | Med | 0.35 | 6.5 | 0.00 | Nov 14, 2025 | Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events | ||
| CVE-2025-9076 | Med | 0.35 | 6.5 | 0.00 | Sep 15, 2025 | Mattermost versions 10.10.x <= 10.10.1 fail to properly sanitize user data during shared channel membership synchronization, which allows malicious or compromised remote clusters to access sensitive user information via unsanitized user objects. This vulnerability affects… | ||
| CVE-2025-6226 | Med | 0.35 | 6.5 | 0.00 | Jul 18, 2025 | Mattermost versions 10.5.x <= 10.5.6, 10.8.x <= 10.8.1, 10.7.x <= 10.7.3, 9.11.x <= 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the… | ||
| CVE-2025-41395 | Med | 0.35 | 6.5 | 0.00 | Apr 24, 2025 | Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to properly validate the props used by the RetrospectivePost custom post type in the Playbooks plugin, which allows an attacker to create a specially crafted post with maliciously crafted props and… | ||
| CVE-2025-35965 | Med | 0.35 | 6.5 | 0.00 | Apr 24, 2025 | Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to validate the uniqueness and quantity of task actions within the UpdateRunTaskActions GraphQL operation, which allows an attacker to create task items containing an excessive number of actions… | ||
| CVE-2025-27933 | Med | 0.35 | 5.4 | 0.00 | Mar 21, 2025 | Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to fail to enforce channel conversion restrictions, which allows members with permission to convert public channels to private ones to also convert private ones to public | ||
| CVE-2024-54682 | Med | 0.35 | 6.5 | 0.00 | Dec 16, 2024 | Mattermost versions 10.1.x <= 10.1.2, 10.0.x <= 10.0.2, 9.11.x <= 9.11.4, 9.5.x <= 9.5.12 fail to limit the file size for slack import file uploads which allows a user to cause a DoS via zip bomb by importing data in a team they are a team admin. |
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number of frames and enforce the file size cap on animated GIF uploads, which allows an authenticated attacker to cause a denial of service via a crafted animated GIF…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify that the channel referenced in an action cookie matches the channel of the target post, which allows an authenticated user without access to a private channel to trigger interactive post…
- risk 0.35cvss 6.4epss 0.00
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to…
- risk 0.35cvss 6.4epss 0.00
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows authenticated users with the {{manage_secure_connections}} permission to obtain remote cluster authentication tokens via…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to filter nil elements from outgoing webhook attachment payloads before processing, which allows an authenticated user to cause a denial of service (server process termination) via…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.2, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail prevent disclosure of created user password which allows a malicious attacker to impersonate a user via the use of some of those passwords.. Mattermost Advisory ID: MMSA-2026-00614
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.5.x <= 11.5.1 fail to verify channel membership when processing AI-assisted message rewrites which allows an authenticated attacker to read the content of threads in private channels and direct messages they do not have access to via a crafted request to…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to validate decompressed archive entry sizes during file extraction which allows authenticated users with file upload permissions to cause a denial of service via crafted zip…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 11.0.x <= 11.0.4, 10.12.x <= 10.12.2, 10.11.x <= 10.11.6 fail to check WebSocket request field for proper UTF-8 format, which allows attacker to crash Calls plug-in via sending malformed request.
- risk 0.35cvss 6.5epss 0.00
Mattermost versions <11 fail to enforce multi-factor authentication on WebSocket connections which allows unauthenticated users to access sensitive information via WebSocket events
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 10.10.x <= 10.10.1 fail to properly sanitize user data during shared channel membership synchronization, which allows malicious or compromised remote clusters to access sensitive user information via unsanitized user objects. This vulnerability affects…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 10.5.x <= 10.5.6, 10.8.x <= 10.8.1, 10.7.x <= 10.7.3, 9.11.x <= 9.11.16 fail to verify authorization when retrieving cached posts by PendingPostID which allows an authenticated user to read posts in private channels they don't have access to via guessing the…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to properly validate the props used by the RetrospectivePost custom post type in the Playbooks plugin, which allows an attacker to create a specially crafted post with maliciously crafted props and…
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.10 fail to validate the uniqueness and quantity of task actions within the UpdateRunTaskActions GraphQL operation, which allows an attacker to create task items containing an excessive number of actions…
- risk 0.35cvss 5.4epss 0.00
Mattermost versions 10.4.x <= 10.4.2, 10.3.x <= 10.3.3, 9.11.x <= 9.11.8 fail to fail to enforce channel conversion restrictions, which allows members with permission to convert public channels to private ones to also convert private ones to public
- risk 0.35cvss 6.5epss 0.00
Mattermost versions 10.1.x <= 10.1.2, 10.0.x <= 10.0.2, 9.11.x <= 9.11.4, 9.5.x <= 9.5.12 fail to limit the file size for slack import file uploads which allows a user to cause a DoS via zip bomb by importing data in a team they are a team admin.
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