CVE-2026-81921: Missing Authorization

Concrete CMS 8.5.3 through 9.5.2 enabled the OAuth 2.0 refresh-token grant using the unmodified upstream League grant, which issued new access tokens from a valid refresh token without re-checking the associated account's active status. A user who obtained a refresh token while active could...

Authentication Bypass by Primary Weakness

Overview Affected versions of this package are vulnerable to Authentication Bypass by Primary Weakness in the OAuth refresh token grant process. An attacker can maintain unauthorized access by using a valid refresh token associated with a deactivated account. Remediation Upgrade...

CVE-2026-9571 Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost

Mattermost versions 11.7.x = 11.7.2, 11.6.x = 11.6.4, 10.11.x = 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allows a deactivated user or an attacker in possession of a valid refresh token to obtain new functional access tokens via the OAuth refresh token...

CVE-2026-9571 Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost

Mattermost versions 11.7.x = 11.7.2, 11.6.x = 11.6.4, 10.11.x = 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allows a deactivated user or an attacker in possession of a valid refresh token to obtain new functional access tokens via the OAuth refresh token...

CVE-2026-9571 Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost

Mattermost versions 11.7.x = 11.7.2, 11.6.x = 11.6.4, 10.11.x = 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allows a deactivated user or an attacker in possession of a valid refresh token to obtain new functional access tokens via the OAuth refresh token...

Incorrect Authorization

Overview better-auth is a The most comprehensive authentication library for TypeScript. Affected versions of this package are vulnerable to Incorrect Authorization in the refreshtoken grant process of the legacy oidcProvider and mcp plugins, where confidential clients are not required to...