OAuth privilege expansion via omitted client identifier
Published Jul 15, 2026 · Updated Jul 15, 2026
Incorrect authorization in Cloudreve 4.12.0 through 4.16.0 allows remote authenticated users to exceed granted OAuth scopes. The access-token issuer omits client_id, so JWT verification leaves scopes out of request context and RequiredScopes skips enforcement as if session authentication were in use. A third-party OAuth app needs a real user to authorize a low-scope token; it can then read or modify that user's files, shares, workflows, settings, and WebDAV state, with admin APIs reachable only when an administrator authorizes it.
Summary
What happened
Incorrect authorization in Cloudreve 4.12.0 through 4.16.0 allows remote authenticated users to exceed granted OAuth scopes. The access-token issuer omits client_id, so JWT verification leaves scopes out of request context and RequiredScopes skips enforcement as if session authentication were in use. A third-party OAuth app needs a real user to authorize a low-scope token; it can then read or modify that user's files, shares, workflows, settings, and WebDAV state, with admin APIs reachable only when an administrator authorizes it.
The record
- CVE
- CVE-2026-54560
- Published
- Jul 15, 2026
- Updated
- Jul 15, 2026
- Vendor
- Cloudreve
- Product
- Cloudreve
- Classifications
- CWE-863, T1550.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 15, 2026CVE publishedPublication date reported by the CVE source.
- Jul 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 4.12.0, < 4.16.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub advisory OAuth scope-bypass reproductionproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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