CVE-2026-77637

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

LOW
3.8
CVSS Score
Published: September 22, 2026 at 03:30 PM UTC
Updated: September 22, 2026 at 06:17 PM UTC
1 product affected across 1 vendorCloudreve

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Severity
LOW3.8
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.18.0
Affected range stops below 4.18.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

3.8LOWGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-862

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