Security Vulnerabilities
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to enforce run-state validation on write operations for finished playbook runs which allows a run participant to modify status, checklists, retrospective content, ownership, and participants on completed runs via REST and GraphQL API requests. Mattermost Advisory ID: MMSA-2026-00675
CVSS Score
4.3
EPSS Score
0.002
Published
2026-08-17
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fail to validate that users have read access to a channel before linking a board to it, which allows an authenticated attacker to discover the membership of private channels on the same team via creating, patching, importing, or bulk-creating boards with an arbitrary channelId. Mattermost Advisory ID: MMSA-2026-00674
CVSS Score
4.3
EPSS Score
0.002
Published
2026-08-17
Mattermost versions 11.8.x <= 11.8.2, 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to restrict channel member role assignment to channel-scoped roles which allows a channel administrator to gain additional channel permissions via the channel member roles API.. Mattermost Advisory ID: MMSA-2026-00697
CVSS Score
6.3
EPSS Score
0.002
Published
2026-08-17
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21, 11.8.x <= 11.8.3 fails to reconcile SchemeAdmin flags with a user's current role which allows a user demoted to System Guest to retain Board Admin privileges and perform admin-only operations via the Boards REST API or UI.. Mattermost Advisory ID: MMSA-2026-00691
CVSS Score
6.3
EPSS Score
0.002
Published
2026-08-17
Mattermost versions 11.7.x <= 11.7.6, 11.8.x <= 11.8.3 The access control policy unassign endpoint fails to re-validate that each target channel still belongs to the requesting admin's team, which allows an authenticated team administrator to remove ABAC (attribute-based access control) policy assignments from channels outside their team via the policy unassign API after a channel has been moved to another team.. Mattermost Advisory ID: MMSA-2026-00718
CVSS Score
4.2
EPSS Score
0.001
Published
2026-08-17
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive import which allows a board member to escalate a guest user to Board Admin via importing a crafted .boardarchive file. Mattermost Advisory ID: MMSA-2026-00672
CVSS Score
5.4
EPSS Score
0.002
Published
2026-08-17
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 Mattermost failed to restrict OAuth deauthorization and personal access token management endpoints to direct user sessions, which allowed an OAuth app with a delegated user token to revoke the user's authorizations or tokens for other integrations via account-management endpoints.. Mattermost Advisory ID: MMSA-2026-00704
CVSS Score
4.3
EPSS Score
0.002
Published
2026-08-17
Exposure of data element to wrong session vulnerability in the JSON plugin of Apache Struts. Per-request parsing state could be shared across concurrent requests, allowing data associated with one request to become observable in another, and configured parsing limits not to be enforced as intended. Populating actions from a JSON request body is not enabled by default; applications that do not use the JSON plugin are not affected.
This issue affects Apache Struts: 7.2.1.
Users are recommended to upgrade to version 7.3.0, which fixes the issue.
CVSS Score
4.3
EPSS Score
0.002
Published
2026-08-15
Exposure of data element to wrong session vulnerability in the JSON plugin of Apache Struts. Per-response serialization state could be shared across concurrent requests, allowing response content associated with one request to become observable in another. Only the SMD / JSON-RPC handling of the JSON interceptor is affected, which is not enabled by default; applications using the json result type are not affected.
This issue affects Apache Struts: 7.2.1.
Users are recommended to upgrade to version 7.3.0, which fixes the issue.
CVSS Score
4.3
EPSS Score
0.002
Published
2026-08-15
Uncontrolled resource consumption vulnerability in Apache Struts. An application that exposes an endpoint collecting Content Security Policy violation reports reads the submitted report into memory without bounding how much it will accept, so a single request can exhaust the heap and deny service to other users. Such endpoints are ordinarily reachable without authentication. The core distribution maps no such endpoint by default; applications that do not collect violation reports are not affected.
This issue affects Apache Struts: from 6.0.0 through 6.10.0, from 7.0.0 through 7.2.1.
Users are recommended to upgrade to version 6.11.0 or 7.3.0, which fixes the issue.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-08-15