CVE-2026-10103 — Authenticated remote cluster can modify or delete posts it does not own in Mattermost Connected Workspaces shared channels
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify post ownership in the shared channel inbound sync handler, which allows an authenticat…
Published: 2026-07-13 · CVSS: 4.3 · CVSS 3.1
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify post ownership in the shared channel inbound sync handler, which allows an authenticated remote cluster to modify or delete posts authored by local users or other remotes via crafted sync messages referencing arbitrary post IDs in channels shared with that remote.. Mattermost Advisory ID: MMSA-2026-00689
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7