CVE-2025-8023
MediumCVSS 6.8Summary
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fail to sanitize path traversal sequences in template file destination paths. A system admin can perform path traversal attacks via malicious path components, potentially enabling malicious file placement outside intended directories.
Risk Assessment
A system admin can exploit path traversal to place files in unexpected locations, potentially leading to overwriting critical files or code execution. However, it requires administrative privileges.
Recommendation
Update Mattermost to a version newer than those listed (e.g., 10.8.4, 10.5.9, 9.11.18, 10.9.3 or later). Review and restrict system admin privileges.
Other vulnerabilities in Mattermost
See all- CVE-2026-2455Medium
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to canonicalize IPv4-mapped IPv6 addresses before reserved IP validation, allowing an attacker to perform SSRF attacks against internal services via IPv4-mapped IPv6 literals such as [::ffff:127.0.0.1].
- CVE-2026-24692Medium
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, and 10.11.x <= 10.11.10 failed to properly enforce read permissions in search API endpoints. Guest users without read permissions could access posts and files in channels via search API requests.
- CVE-2026-22545Low
Mattermost versions 10.11.x <= 10.11.10 fail to validate the user's authentication method when processing an account auth type switch. An authenticated attacker can change the account password without confirmation by falsely claiming a different auth provider.
- CVE-2026-21386Medium
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to use consistent error responses when handling the /mute command. An authenticated team member can enumerate private channels they are not authorized to know about via differing error messages for nonexistent versus private channels.
- CVE-2026-4265Medium
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to validate team-specific upload_file permissions, allowing a guest user to post files in channels where they lack upload_file permission by uploading files in a team where they have permission and reusing the file metadata in a POST request to a different team.
- CVE-2026-2578Medium
Mattermost versions 11.3.x <= 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion, allowing channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event. Advisory ID: MMSA-2026-00579.
- CVE-2026-2463Medium
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to filter invite IDs based on user permissions, allowing regular users to bypass access control restrictions and register unauthorized accounts via leaked invite IDs during team creation.
- CVE-2026-2458Medium
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, and 10.11.x <= 10.11.10 fail to properly validate team membership when searching channels, allowing a removed team member to enumerate all public channels within a private team via the channel search API endpoint.
- CVE-2026-2457Medium
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, and 10.11.x <= 10.11.10 fail to sanitize client-supplied post metadata. An authenticated attacker can spoof permalink embeds impersonating other users via crafted PUT requests to the post update API endpoint.
- CVE-2026-2456Medium
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to limit the size of responses from integration action endpoints. An authenticated attacker can cause server memory exhaustion and denial of service via a malicious integration server returning an arbitrarily large response when a user clicks an interactive message button.
Original NVD description (English source)
Mattermost versions 10.8.x <= 10.8.3, 10.5.x <= 10.5.8, 9.11.x <= 9.11.17, 10.9.x <= 10.9.2 fails to sanitize path traversal sequences in template file destination paths, which allows a system admin to perform path traversal attacks via malicious path components, potentially enabling malicious file placement outside intended directories.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS