CVE-2026-28735
Fixed in a distro release EPSS <1%CVSS 5.4
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the OAuth token scope on the callback which allows an authenticated Mattermost user to gain access to private repositories via modifying the scope parameter in the GitHub authorization URL.. Mattermost Advisory ID: MMSA-2026-00628
Products: Mattermost
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| Go | github.com/mattermost/mattermost-plugin-github | 1.0.1-0.20260318132218-6e6b740c4852 |
| Go | github.com/mattermost/mattermost-server | 11.6.1 |
| Go | github.com/mattermost/mattermost-server | 11.5.4 |
| Go | github.com/mattermost/mattermost-server | 11.4.5 |
| Go | github.com/mattermost/mattermost-server | 10.11.15 |
| Go | github.com/mattermost/mattermost-server | 10.11.15+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.4.5+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.5.4+incompatible |
| Go | github.com/mattermost/mattermost-server | 11.6.1+incompatible |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 |