CVE-2026-77637

LOW 3.8

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

CVSS Score

3.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-862
Vendor	cloudreve
Product	cloudreve
Published	Sep 22, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Affected Versions

cloudreve / cloudreve

< 4.18.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/cloudreve/cloudreve/security/advisories/GHSA-w89x-c962-c44g github.com: https://github.com/cloudreve/cloudreve/commit/bce08f88e9d8f881e78fd18e7a6598b31922c492 github.com: https://github.com/cloudreve/cloudreve/releases/tag/4.18.0