CVE-2026-28732
Fixed in a distro release EPSS <1%CVSS 4.3
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to enforce slash command trigger-word uniqueness during command updates which allows an authenticated team member with Manage Own Slash Commands permission to hijack and impersonate existing system or custom slash commands via editing their own slash command trigger to an already-registered trigger through the command update API. Mattermost Advisory ID: MMSA-2026-00597
Products: Mattermost
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| Go | github.com/mattermost/mattermost-server | 5.3.2-0.20260306123948-f5fe8ded6b63 |
| Go | github.com/mattermost/mattermost-server | 10.11.14+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.4.4+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.5.2+incompatible |
| Go | github.com/mattermost/mattermost-server/v5 | no fix |
| Go | github.com/mattermost/mattermost-server/v6 | no fix |
| Go | github.com/mattermost/mattermost/server/v8 | 11.5.2 |
| Go | github.com/mattermost/mattermost/server/v8 | 10.11.14 |
| Go | github.com/mattermost/mattermost/server/v8 | 11.4.4 |
| Go | github.com/mattermost/mattermost/server/v8 | 8.0.0-20260306123948-f5fe8ded6b63 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 |