Vulnerability · Published Sep 22, 2026 · Assigned by GitHub_M
CVE-2026-79913Cloudreve: SSRF guard bypass: checkIP does not decode IPv6-transition wrappers (NAT64, IPv4-compatible, 6to4) reaching internal and cloud-metadata addresses
Medium 6.5
In plain English
A medium-severity server-side request forgery in cloudreve from cloudreve. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Cloudreve is a self-hosted file management and sharing system. Prior to 4.18.0, the ValidateExternalURL server-side request forgery 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. This issue is fixed in version 4.18.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/cloudreve/Cloudreve | no fix listed | GO-2026-6572 |
| Go | github.com/cloudreve/Cloudreve/v3 | no fix listed | GO-2026-6572 |
| Go | github.com/cloudreve/Cloudreve/v4 | 4.0.0-20260715072853-1c5cad6dec7e | GHSA-jvh5-97xg-v99f |
| Go | github.com/cloudreve/Cloudreve/v4 | 4.0.0-20260715072853-1c5cad6dec7e | GO-2026-6572 |
Affected products (as reported)
Weakness: CWE-918, CWE-697 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N