CVE-2026-28732
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
- CVSS 3.1
- 4.3
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 4% of CVEs (scores of 2026-10-25)
- CWE
- CWE-863
- Published
- Modified
- Record from
- the NVD, synced
Affected
- mattermost:mattermost_server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-wvcv-9xpm-7mqc | Go | github.com/mattermost/mattermost/server/v8 | >=11.5.0 <11.5.2 | 11.5.2 |
| GHSA-wvcv-9xpm-7mqc | Go | github.com/mattermost/mattermost/server/v8 | >=10.11.0 <10.11.14 | 10.11.14 |
| GHSA-wvcv-9xpm-7mqc | Go | github.com/mattermost/mattermost/server/v8 | >=11.4.0 <11.4.4 | 11.4.4 |
| GHSA-wvcv-9xpm-7mqc | Go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20260306123948-f5fe8ded6b63 | 8.0.0-20260306123948-f5fe8ded6b63 |
| GHSA-wvcv-9xpm-7mqc | Go | github.com/mattermost/mattermost-server | <5.3.2-0.20260306123948-f5fe8ded6b63 | 5.3.2-0.20260306123948-f5fe8ded6b63 |
| GO-2026-5726 | Go | github.com/mattermost/mattermost-server | >=10.11.0+incompatible <10.11.14+incompatible >=11.4.0+incompatible <11.4.4+incompatible >=11.5.0+incompatible <11.5.2+incompatible | 10.11.14+incompatible, 11.4.4+incompatible, 11.5.2+incompatible |
| GO-2026-5726 | Go | github.com/mattermost/mattermost-server/v5 | all versions | no fix published |
| GO-2026-5726 | Go | github.com/mattermost/mattermost-server/v6 | all versions | no fix published |
| GO-2026-5726 | Go | github.com/mattermost/mattermost/server/v8 | <8.0.0-20260306123948-f5fe8ded6b63 | 8.0.0-20260306123948-f5fe8ded6b63 |