VULNERABILITY INTELLIGENCE

CVE-2026-28735

CVSS score5.4 MEDIUM
EPSS probability0.14%
CISA KEVNot currently listed
Published2026-05-22
Last modified2026-07-23
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Description

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

Weakness classification

  • responsibledisclosure@mattermost.com: CWE-863

Primary references