CVE-2026-77637 json
Cloudreve: Privilege Scope Bypass: State-Mutating Admin Operations Accessible via Read-Only OAuth Scope
published 2026-09-22 47 d ago modified 2026-10-01 38 d ago also GHSA-w89x-c962-c44g , GO-2026-6576 , EUVD-2026-84529
- cvss
- 3.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 25%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- go github.com/cloudreve/Cloudreve/v4 4.0.0-20260715070110-bce08f88e9d8
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 47 d ago
Exploit prediction
0.33% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 3.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N |
| GitHub | 3.1 | 3.8 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/cloudreve/Cloudreve/v4 | <4.0.0-20260715070110-bce08f88e9d8 |
4.0.0-20260715070110-bce08f88e9d8 |
| go | github.com/cloudreve/Cloudreve | all versions |
no fix listed |
| go | github.com/cloudreve/Cloudreve/v3 | all versions |
no fix listed |
Affected products
- cloudreve cloudreve
Classification
- Weakness
-
- CWE-862 Missing Authorization
References
-
github.com
/cloudreve/cloudreve/commit/bce08f88e9d8f881e78fd18e7a6598b31922c492
web
-
github.com
/cloudreve/cloudreve/security/advisories/GHSA-w89x-c962-c44g
web, advisory
-
github.com
/cloudreve/cloudreve/releases/tag/4.18.0
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-77637
advisory
-
github.com
/cloudreve/cloudreve
package
Sources
- CVE List CVE-2026-77637
- GitHub Advisory GHSA-w89x-c962-c44g
- NVD CVE-2026-77637
- OSV GO-2026-6576
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