CVE-2026-28735mediumCWE-863

CVE-2026-28735: medium-severity vulnerability in Mattermost

GitHub OAuth Scope Validation

Published

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 5.4epss 0.1%
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
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Affected products
Mattermost · Mattermost
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