PT-2026-115517 · Mattermost · Mattermost

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CVE-2026-19603

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Published

2026-10-16

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Updated

2026-10-16

CVSS v3.1

4.3

Medium

VectorAV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to sanitize the active channel field returned by the user status API endpoints, which allows an authenticated user to learn the channel ID of a private channel another user is actively viewing via the status endpoints, without being a member of that channel. Mattermost Advisory ID: MMSA-2026-00765

Fix

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Weakness Enumeration

Related Identifiers

CVE-2026-19603

Affected Products

Mattermost