What’s Vulnerable › Vulnerabilities

CVE-2026-77637: Cloudreve: Privilege Scope Bypass: State-Mutating Admin Operations Accessible via Read-Only OAuth Scope

• Severity: low (CVSS 3.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-22 · updated 2026-09-22
• Weakness: CWE-862

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 products

• cloudreve: before 4.18.0

References

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

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