Signal is active with 1 mentions in latest observed window
Recommended action window: Monitor and triage in normal cycle
NVD description
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate that a remote cluster has access to a channel before processing membership removal requests during shared channel membership sync, which allows a malicious remote cluster to remove any user from any channel, including private channels, via crafted membership sync messages targeting channels the remote cluster is not authorized to access. Mattermost Advisory ID: MMSA-2026-00576
Priority
LOW
Exploitation
NONE
PoC
NONE
Patch
NONE
Momentum
NONE
If you run products in this scope, you should treat this CVE as relevant to your environment.
CVE-2026-28759 Unauthorized Channel Membership Removal in Mattermost via Unvalidated Remote Cluster Access https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-28759
Post summary
The text lists CVE‑2026‑28759 and provides a brief technical description of an authorization bypass in Mattermost, but offers no evidence of a PoC, exploit, patch, or active exploitation.
1 of 1 entries
| Part | Vendor | Product | Version | Target SW | Target HW |
|---|---|---|---|---|---|
| App | mattermost | mattermost_server | - | - | - |