{"id":"CVE-2026-58404","aliases":["GHSA-r46f-3rpw-hxrv","GO-2026-5606"],"url":"https://o3.security/vulnerability/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.","published":"2026-07-06T19:16:15.945Z","modified":"2026-08-12T03:51:17.268917081Z","cvss":null,"epss":{"score":0.00368,"percentile":0.30184,"asOf":"2026-09-12"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/gohugoio/hugo","fixedVersion":"0.163.1"}],"fix":{"url":"https://github.com/gohugoio/hugo/commit/a00b5c72ac57afe26df6688ece3ca544a56df372","label":"gohugoio/hugo@a00b5c7"},"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:17.268917081Z"}}