---
id: CVE-2026-77633
title: Cloudreve is a self-hosted file management and sharing system
summary: >-
  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
  unconditiona…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H'
cwe:
  - CWE-362
  - CWE-367
  - CWE-770
vendor: cloudreve
product: cloudreve
affected:
  - cloudreve < 4.18.0
published: '2026-09-22'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T16:17:55.953'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77633'
references:
  - url: >-
      https://github.com/cloudreve/cloudreve/commit/7329602751c00bb4136fe9ad8b364d0df70773df
    label: security-advisories@github.com
  - url: 'https://github.com/cloudreve/cloudreve/releases/tag/4.18.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/cloudreve/cloudreve/security/advisories/GHSA-xj3h-wwxq-gfcj
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77633'
  - url: 'https://github.com/advisories/GHSA-xj3h-wwxq-gfcj'
  - url: 'https://github.com/cloudreve/cloudreve'
tags:
  - nvd
  - cve.org
  - ghsa
  - go
  - osv
ingestedAt: '2026-09-22T16:06:00.491Z'
aliases:
  - GHSA-xj3h-wwxq-gfcj
ecosystem: go
patched:
  - github.com/cloudreve/Cloudreve/v4 4.0.0-20260715025621-7329602751c0
epss: 0.00368
epssPercentile: 0.30702
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-77633)

Affected packages:

- `github.com/cloudreve/Cloudreve/v4 < 4.0.0-20260715025621-7329602751c0`

Patched in:

- `github.com/cloudreve/Cloudreve/v4 4.0.0-20260715025621-7329602751c0`

Source: https://github.com/advisories/GHSA-xj3h-wwxq-gfcj