[ CVE-2026-77637 · Published 22 Sep 2026 ]

Cloudreve: Privilege Scope Bypass: State-Mutating Admin Operations Accessible via Read-Only OAuth Scope

CVSS 3.8 EPSS <1%Fix available

[ Description ]Official description

Cloudreve is a self-hosted file management and sharing system. Prior to 4.18.0, tool.GET("wopi") and tool.POST("mail") in routers/router.go inherit ScopeAdminRead but omit the RequiredScopes(types.ScopeAdminWrite) middleware applied to neighboring state-changing admin tool routes. An OAuth application or API key limited to Admin.Read can therefore probe configured WOPI service endpoints and send arbitrary test email through the server SMTP configuration, exceeding the token's intended read-only authorization boundary. This issue is fixed in version 4.18.0.

[ Fixes ]Fixes and patches

[ Packages ]Affected open-source packages

  • github.com/cloudreve/Cloudreve/v4 goAffected < 4.0.0-20260715070110-bce08f88e9d8 · fixed in 4.0.0-20260715070110-bce08f88e9d8 · GHSA-w89x-c962-c44g