CVE-2026-77633

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 v3 7.1 HIGH

7.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 4.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/cloudreve/cloudreve/commit/7329602751c00bb4136fe9ad8b364d0df70773df
https://github.com/cloudreve/cloudreve/releases/tag/4.18.0
https://github.com/cloudreve/cloudreve/security/advisories/GHSA-xj3h-wwxq-gfcj

Configurations

No configuration.

History

22 Sep 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-22 16:17

Updated : 2026-09-26 00:16

NVD link : CVE-2026-77633

Mitre link : CVE-2026-77633

CVE.ORG link : CVE-2026-77633

JSON object : View

Products Affected

No product.

CWE

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CWE-367

Time-of-check Time-of-use (TOCTOU) Race Condition

CWE-770

Allocation of Resources Without Limits or Throttling

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