CVE-2026-101048

Cloudreve before 4.16.1 fails to revalidate share access when restoring cached navigator state from a context_hint UUID. Attackers who previously had valid share access can replay the cached hint to generate signed file URLs for up to 300 seconds after the share is deleted, expires, or reaches zero remaining downloads.

Cloudreve before 4.16.1 fails to properly sanitize file paths returned by remote downloaders, allowing authenticated users to create files outside the selected destination directory. Attackers can exploit path traversal sequences in downloader metadata to write files to unexpected locations.

In Cloudreve prior to 4.18.0, the ValidateExternalURL server-side request forgery (SSRF) guard in pkg/request/ssrf.go passes resolved addresses to checkIP without decoding NAT64, IPv4-compatible, and 6to4 IPv4-in-IPv6 transition forms. An authenticated user with remote-download access can provide SrcUri through RemoteDownloadTask.createDownloadTask so a wrapper embedding a loopback, private, link-local, or cloud metadata IPv4 address is classified as public and fetched, exposing internal service responses and cloud instance credentials. IPv4-mapped IPv6 addresses remain blocked because Go converts that form with net.IP.To4.

Cloudreve before version 4.18.0 lacks the RequiredScopes(types.ScopeAdminWrite) middleware on tool.GET("wopi") and tool.POST("mail") routes, which inherit ScopeAdminRead. An OAuth application or API key with Admin.Read can probe configured WOPI endpoints and send arbitrary test emails via the server SMTP configuration, exceeding read-only authorization boundaries.

Cloudreve is a self-hosted file management and sharing system. Prior to 4.18.0, PrepareUpload checks a stale in-memory user storage value 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, exceeding the account quota and exhausting host storage.

In Cloudreve before version 4.17.0, WOPI session validation uses only the session-id prefix of the access token and does not enforce the requested action, allowing a malicious viewer to forge the token suffix and invoke file write operations.

Vulnerability in Cloudreve before 4.17.0, where the POST /api/v4/admin/policy/oauth/signin endpoint requires only Admin.Read permission but allows modification of OneDrive storage policy credentials without Admin.Write, enabling changes to secret and app_id.

In Cloudreve before version 4.17.0, a single-file share event-stream subscription resolves the share root to the owner's parent folder and subscribes to it, allowing an authenticated share recipient to receive information about unshared sibling files and folders.

Cloudreve before version 4.17.0 has a vulnerability in thumbnail and avatar decoders that limit compressed file size but not decoded pixel dimensions. An authenticated user can submit a small PNG, JPEG, or GIF that triggers unbounded memory allocation and terminates the Cloudreve process due to an out-of-memory error.

Cloudreve before version 4.17.0 has a vulnerability in the GET /api/v4/user/search endpoint that calls SearchActive without adding a StatusActive predicate and serializes matches at RedactLevelUser. This allows any logged-in user to enumerate email addresses and profile metadata for inactive or banned accounts.