Vulnerability in github.com/cloudreve/Cloudreve/v4 (CVE-2026-79913)
Summary
Vulnerability in github.com/cloudreve/Cloudreve/v4 (CVE-2026-79913). Confidential information can be exposed externally. Exploitable via ValidateExternalURL. Mitigation: upgrade to 4.0.0-20260715072853-1c5cad6dec7e or later.
Original description
The description as published by the source.
Summary
Cloudreve's server-side request forgery guard ValidateExternalURL (pkg/request/ssrf.go) resolves a user-supplied URL host and rejects it when any resolved IP is a loopback, private, link-local, multicast, unspecified, CGNAT, or the cloud-metadata address. The classification is performed by checkIP, which uses Go's net.IP builtins (IsLoopback, IsPrivate, IsLinkLocalUnicast, ...) directly on the resolved address. These builtins inspect only the outer IPv6 address and do not decode IPv4-in-IPv6 transition wrappers. An attacker who controls a hostname's AAAA record (or, on a DNS64/NAT64 network, any hostname) can point the remote-download URL at a NAT64 well-known-prefix address (64:ff9b::a.b.c.d, RFC 6052), an IPv4-compatible address (::a.b.c.d, RFC 4291), or a 6to4 address (2002:AABB:CCDD::, RFC 3056) that wraps an internal IPv4. Go classifies these wrappers as ordinary global IPv6 addresses, so checkIP accepts them; the network then delivers the request to the embedded internal IPv4 (loopback, RFC 1918, or the cloud instance metadata service 169.254.169.254). This bypasses the SSRF guard that was added to block direct access to internal services.
Affected component and versions
- Component:
pkg/request/ssrf.go(ValidateExternalURL/checkIP), reached from the remote-download workflowpkg/filemanager/workflows/remote_download.go(RemoteDownloadTask.createDownloadTask, which passes the user-suppliedSrcUrito `ValidateExtern…
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-2026-79913 has been found in github.com/cloudreve/Cloudreve/v4.
Attackers can target a specific entry point like ValidateExternalURL over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: upgrade github.com/cloudreve/Cloudreve/v4 to 4.0.0-20260715072853-1c5cad6dec7e or later.
If unsure, ask your IT team or search "github.com/cloudreve/Cloudreve/v4 CVE-2026-79913" on the vendor's site.
CVE-2026-79913 (github.com/cloudreve/Cloudreve/v4) — CWE-697 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: ValidateExternalURL / checkIP / net.IP / IsLoopback
Patched: 4.0.0-20260715072853-1c5cad6dec7e — 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.
A vulnerability (CWE-697) exists in github.com/cloudreve/Cloudreve/v4. Attackers reach the vulnerable code path via ValidateExternalURL.
Check the vendor advisory for the affected versions of github.com/cloudreve/Cloudreve/v4. Attack surface: ValidateExternalURL / checkIP / net.IP / IsLoopback.
Severity: Medium (CVSS 6.5/10). Confidential information can be exposed externally.
Update to 4.0.0-20260715072853-1c5cad6dec7e.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. 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。 -
2Apply patch patch
Upgrade github.com/cloudreve/Cloudreve/v4 to 4.0.0-20260715072853-1c5cad6dec7eステージング環境で 4.0.0-20260715072853-1c5cad6dec7e 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を含めること。
-
3Post-deployment verification verify
Confirm patched version is live in production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。本番ではアクセスログ・WAF 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
- web github.com