Authorization Flaw in github.com/cloudreve/Cloudreve/v4 (CVE-2026-54563)
Summary
Vulnerability in github.com/cloudreve/Cloudreve/v4 (CVE-2026-54563). Confidential information can be exposed externally. Exploitable via GET /dav/. Mitigation: upgrade to 4.0.0-20260606032813-26b6b1044b02 or later.
Original description
The description as published by the source.
Summary
A Cloudreve WebDAV account stores a uri that defines the account's root folder. The WebDAV request handler (stripPrefix in pkg/webdav/webdav.go) trims the /dav prefix from the request path and joins the remainder to that root with fs.URI.JoinRaw, but never checks that the joined URI stays inside the root.
Go's net/http decodes %2e%2e to .. and %2f to / in r.URL.Path before the handler sees it, and JoinRaw resolves .. segments through the standard library's url.URL.JoinPath. A request such as GET /dav/%2e%2e/outside.txt against a credential rooted at cloudreve://my/restricted therefore resolves to cloudreve://my/outside.txt. A scoped DAV credential can read and list files outside its configured folder; a writable scoped credential can also create, overwrite, move, and delete them.
The escape stays inside the same Cloudreve user's namespace because downstream DBFS owner checks still apply. It does not cross into another user's files or onto the OS filesystem. What it breaks is the per-folder WebDAV-account boundary — the entire reason scoped DAV accounts exist (delegating limited access to a sync client or a third party).
Technical Detail
Root cause
stripPrefix joins the request suffix onto the account base with no containment check:
// pkg/webdav/webdav.go @ 54dc81d
func stripPrefix(p string, u *ent.User) (string, *fs.URI, int, error) {
base, err := fs.NewUriFromString(u.Edges.DavAccounts[0].URI)
if err != ni…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-54563 has been found in github.com/cloudreve/Cloudreve/v4.
Attackers can target a specific entry point like GET /dav/ over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: upgrade github.com/cloudreve/Cloudreve/v4 to 4.0.0-20260606032813-26b6b1044b02 or later.
If unsure, ask your IT team or search "github.com/cloudreve/Cloudreve/v4 CVE-2026-54563" on the vendor's site.
CVE-2026-54563 (github.com/cloudreve/Cloudreve/v4) — CWE-863 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /dav/ / PUT /dav/ / uri / stripPrefix
Patched: 4.0.0-20260606032813-26b6b1044b02 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Incorrect authorization (CWE-863) exists in github.com/cloudreve/Cloudreve/v4. Attackers reach the vulnerable code path via GET /dav/.
Check the vendor advisory for the affected versions of github.com/cloudreve/Cloudreve/v4. Attack surface: GET /dav/ / PUT /dav/ / uri / stripPrefix.
Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.
Update to 4.0.0-20260606032813-26b6b1044b02.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /dav/ requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/cloudreve/Cloudreve/v4' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/cloudreve/Cloudreve/v4' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/cloudreve/Cloudreve/v4を grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /dav/' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /dav/への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade github.com/cloudreve/Cloudreve/v4 to 4.0.0-20260606032813-26b6b1044b02ステージング環境で 4.0.0-20260606032813-26b6b1044b02 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /dav/ on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com