CVE-2026-77637 json
Cloudreve: Privilege Scope Bypass: State-Mutating Admin Operations Accessible via Read-Only OAuth Scope
published last mo. modified last mo. also EUVD-2026-84529 , GHSA-w89x-c962-c44g , GO-2026-6576
- 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
- cloudreve cloudreve 4.18.0
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- last mo.
Exploit prediction
0.33% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-11).
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
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.