Vulnerability Description
Cloudreve is a self-hosted file management and sharing system. Prior to 4.18.0, PrepareUpload in pkg/filemanager/fs/dbfs/upload.go checks a stale in-memory user storage value through validateUserCapacity and later applies an unconditional storage charge outside the same quota-enforcing transaction. An authenticated user with Files.Write permission can issue concurrent upload-session requests that read the same capacity snapshot, all pass the MaxStorage check, and reserve their declared sizes through CommitWithStorageDiff. The resulting reservations can exceed the account quota and can be materialized as chunked uploads that exhaust host storage and deny uploads to other users. The default local-storage policy and default User group are affected. This issue is fixed in version 4.18.0.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/cloudreve/cloudreve/commit/7329602751c00bb4136fe9ad8b364d0df7
- https://github.com/cloudreve/cloudreve/releases/tag/4.18.0
- https://github.com/cloudreve/cloudreve/security/advisories/GHSA-xj3h-wwxq-gfcj
FAQ
What is CVE-2026-77633?
CVE-2026-77633 is a vulnerability with a CVSS score of 7.1 (HIGH). Cloudreve is a self-hosted file management and sharing system. Prior to 4.18.0, PrepareUpload in pkg/filemanager/fs/dbfs/upload.go checks a stale in-memory user storage value through validateUserCapac...
How severe is CVE-2026-77633?
CVE-2026-77633 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-77633?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.