{"id":"CVE-2026-58404","state":"PUBLISHED","title":"Hugo security.http.urls deny rules bypassed by alternate IPv4 encodings","description":"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.","publishedAt":"2026-07-06T19:16:15.945Z","updatedAt":"2026-07-07T15:08:53.514Z","severity":{"score":4.6,"label":"Medium","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["gohugoio hugo"],"affected":[{"vendor":"gohugoio","product":"hugo","versions":[{"version":">= v0.162.0, < v0.163.1","status":"affected"}]}],"references":["https://github.com/gohugoio/hugo/security/advisories/GHSA-r46f-3rpw-hxrv","https://github.com/gohugoio/hugo/pull/15020","https://github.com/gohugoio/hugo/commit/a00b5c72ac57afe26df6688ece3ca544a56df372","https://github.com/gohugoio/hugo/releases/tag/v0.163.1"],"weaknesses":["CWE-918"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/58xxx/CVE-2026-58404.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-58404","state":"PUBLISHED","datePublished":"2026-07-06T19:16:15.945Z","dateUpdated":"2026-07-07T15:08:53.514Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-30T18:19:58.379Z"},"containers":{"cna":{"title":"Hugo security.http.urls deny rules bypassed by alternate IPv4 encodings","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"gohugoio","product":"hugo","versions":[{"version":">= v0.162.0, < v0.163.1","status":"affected"}]}],"references":[{"url":"https://github.com/gohugoio/hugo/security/advisories/GHSA-r46f-3rpw-hxrv","name":"https://github.com/gohugoio/hugo/security/advisories/GHSA-r46f-3rpw-hxrv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/gohugoio/hugo/pull/15020","name":"https://github.com/gohugoio/hugo/pull/15020","tags":["x_refsource_MISC"]},{"url":"https://github.com/gohugoio/hugo/commit/a00b5c72ac57afe26df6688ece3ca544a56df372","name":"https://github.com/gohugoio/hugo/commit/a00b5c72ac57afe26df6688ece3ca544a56df372","tags":["x_refsource_MISC"]},{"url":"https://github.com/gohugoio/hugo/releases/tag/v0.163.1","name":"https://github.com/gohugoio/hugo/releases/tag/v0.163.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"PASSIVE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":4.6,"baseSeverity":"MEDIUM","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-918","lang":"en","description":"CWE-918: Server-Side Request Forgery (SSRF)","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-06T19:16:15.945Z"},"source":{"advisory":"GHSA-r46f-3rpw-hxrv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-07T15:08:15.371330Z","id":"CVE-2026-58404","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-07T15:08:53.514Z"}}]}}}