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 which allows a guest user to post files in channels where they lack upload_file permission via uploading files in a team where they have permission and reusing the file metadata in a POST request to a different team. Mattermost Advisory ID: MMSA-2025-00553
Metrics
Affected Vendors & Products
References
| Link | Providers |
|---|---|
| https://mattermost.com/security-updates |
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History
Wed, 18 Mar 2026 17:45:00 +0000
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| First Time appeared |
Mattermost
Mattermost mattermost Server |
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| CPEs | cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Mattermost
Mattermost mattermost Server |
Mon, 16 Mar 2026 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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Mon, 16 Mar 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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 which allows a guest user to post files in channels where they lack upload_file permission via uploading files in a team where they have permission and reusing the file metadata in a POST request to a different team. Mattermost Advisory ID: MMSA-2025-00553 | |
| Title | Guest user can upload files without permission across teams | |
| Weaknesses | CWE-863 | |
| References |
| |
| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: Mattermost
Published: 2026-03-16T12:07:14.659Z
Updated: 2026-03-16T13:49:55.080Z
Reserved: 2026-03-16T12:05:32.172Z
Link: CVE-2026-4265
Updated: 2026-03-16T13:43:37.311Z
Status : Analyzed
Published: 2026-03-16T14:20:19.733
Modified: 2026-03-18T17:41:56.197
Link: CVE-2026-4265
No data.
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