{"id":"CVE-2026-18424","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-18424","summary":"Concrete CMS 9.0.0 to 9.5.2 is vulnerable to SSRF protection bypass in remote file import when multiple URLs share a host but use different ports","details":"Concrete CMS 9.0.0 to 9.5.2 is vulnerable to Server-Side Request Forgery iremote file import via cross-port reuse of a host's validated DNS pin. When multiple remote URLs share the same host, only the first `ValidatedRemoteUrl` is retained and reused for every later URL with that host. A low-privileged authenticated user permitted to import files could therefore supply a DNS-rebinding host that resolved to a public address during validation and to a private or loopback address during the unpinned download, causing the server to fetch internal-only resources such as loopback services, internal admin panels, or cloud metadata endpoints and to save the responses into the file manager. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N. Thanks Ahmad Wicaksono (sonix03) for reporting.","published":"2026-09-15T19:49:48.589Z","modified":"2026-09-23T03:46:32.262413019Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"ADVISORY","url":"https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18424.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-18424"},{"type":"PACKAGE","url":"https://github.com/concretecms/concretecms"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-23T03:46:32.262413019Z"}}