CVE-2026-4265

MediumCVSS 4.3/10Last modified Jun 17, 2026

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

Metrics

CVSS 3.1 4.3/10CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Weakness enumeration

CWE-863

Affected software

No affected versions have been published.

Timeline

Published: Mar 16, 2026
Last modified: Jun 17, 2026
NVD status: Analyzed

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