{"id":"CVE-2026-58404","summary":"Hugo security.http.urls deny rules bypassed by alternate IPv4 encodings","details":"Hugo is a static site generator. From v0.162.0 through v0.163.0, the default security.http.urls policy denies requests to loopback, internal, and cloud-metadata IPv4 literals, but the deny rule only matched dotted-decimal notation, so alternate IPv4 encodings of the same addresses, including integer, hex, or octal, passed the policy. When a template passes an untrusted or data-derived URL to resources.GetRemote and the host platform uses the cgo system resolver, these encodings resolve to the blocked address, allowing build-time server-side requests to loopback and internal services, including the cloud-metadata endpoint in hosted or CI builds; the same check is reused on redirects, so the gap also applies to each redirect hop. This issue is fixed in v0.163.1.","aliases":["GHSA-r46f-3rpw-hxrv","GO-2026-5606"],"modified":"2026-08-12T03:30:40.050406524Z","published":"2026-07-06T19:16:15.945Z","database_specific":{"cwe_ids":["CWE-918"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58404.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/gohugoio/hugo/releases/tag/v0.163.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58404.json"},{"type":"ADVISORY","url":"https://github.com/gohugoio/hugo/security/advisories/GHSA-r46f-3rpw-hxrv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58404"},{"type":"FIX","url":"https://github.com/gohugoio/hugo/commit/a00b5c72ac57afe26df6688ece3ca544a56df372"},{"type":"FIX","url":"https://github.com/gohugoio/hugo/pull/15020"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/gohugoio/hugo","events":[{"introduced":"076dfe13d0f789e3d9586b192f8f7f3329c26990"},{"fixed":"2a4fd58818ffdf45bbb2a97ab119bb4c46cd93f0"},{"fixed":"a00b5c72ac57afe26df6688ece3ca544a56df372"}],"database_specific":{"extracted_events":[{"introduced":"0.162.0"},{"fixed":"0.163.1"}],"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:gohugo:hugo:*:*:*:*:*:*:*:*"}}],"versions":["v0.163.0","v0.162.1","v0.162.0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-58404.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"}]}