{"id":"CVE-2026-100724","aliases":[],"cve":{"records":[{"id":"CVE-2026-100724","source":"VulnCheck","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-09-26T02:40:56.226Z","published":"2026-09-27T01:28:30.710Z","modified":"2026-10-29T21:15:26.111Z"}],"publishers":[{"name":"VulnCheck","role":"CNA","organizationId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","modified":"2026-10-29T21:15:26.111Z"},{"name":"CISA-ADP","role":"ADP","organizationId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","modified":"2026-09-30T15:15:23.058Z"}],"references":[{"url":"https://github.com/http4k/http4k/security/advisories/GHSA-jrpc-7vxp-69p6","tags":["vendor-advisory"],"source":"VulnCheck"},{"url":"https://github.com/http4k/http4k/commit/0121b05537","tags":["patch"],"source":"VulnCheck"},{"url":"https://github.com/http4k/http4k/commit/54c6385615","tags":["patch"],"source":"VulnCheck"},{"url":"https://www.vulncheck.com/advisories/http4k-before-6.49.0.0-host-header-routing-bypass-via-reverseproxy","tags":["third-party-advisory"],"source":"VulnCheck"}],"weaknesses":[{"id":"CWE-444","description":"Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","source":"VulnCheck"}],"applicability":[],"prioritization":[{"source":"CISA-ADP","type":"SSVC","role":"CISA Coordinator","timestamp":"2026-09-30T15:15:13.800731Z","decisions":[{"name":"Exploitation","value":"none"},{"name":"Automatable","value":"no"},{"name":"Technical Impact","value":"partial"}]}]},"title":"http4k before 6.49.0.0 Host Header Routing Bypass via reverseProxy","titleSource":"VulnCheck","descriptionSource":"VulnCheck","description":"http4k (Maven package org.http4k:http4k-core) before 6.49.0.0, 5.42.0.0 and 4.51.0.0 uses substring (Contains) matching on the Host header by default in reverseProxy() and reverseProxyRouting() when dispatching to configured virtual hosts. If these functions are deployed as a public-facing inbound HTTP handler with two or more configured virtual hosts, a remote attacker can supply a Host header that merely contains a configured vhost name (for example Host: admin.evil.com for a vhost configured as \"admin\") and be routed to that vhost, bypassing routing-based authorization. The intended outbound-dispatch and test-time uses, where the Host value is set by the calling application, are not affected.","score":6.3,"severity":"medium","published":"2026-09-27T01:28:30.710Z","modified":"2026-10-29T21:15:26.111Z","withdrawn":false,"knownExploited":false,"affected":[],"products":[{"vendor":"http4k","name":"http4k","platforms":[],"versions":[{"version":"6.0.0.0","status":"affected","lessThan":"6.49.0.0","versionType":"custom"},{"version":"6.49.0.0","status":"unaffected","versionType":"custom"}],"defaultStatus":"unaffected","packageURL":"pkg:maven/org.http4k/http4k-core","packageIdentity":{"ecosystem":"Maven","name":"org.http4k:http4k-core"},"cpes":[],"source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2026-100724"},{"vendor":"http4k","name":"http4k","platforms":[],"versions":[{"version":"5.0.0.0","status":"affected","lessThan":"5.42.0.0","versionType":"custom"},{"version":"5.42.0.0","status":"unaffected","versionType":"custom"}],"defaultStatus":"unaffected","packageURL":"pkg:maven/org.http4k/http4k-core","packageIdentity":{"ecosystem":"Maven","name":"org.http4k:http4k-core"},"cpes":[],"source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2026-100724"},{"vendor":"http4k","name":"http4k","platforms":[],"versions":[{"version":"0","status":"affected","lessThan":"4.51.0.0","versionType":"custom"},{"version":"4.51.0.0","status":"unaffected","versionType":"custom"}],"defaultStatus":"unaffected","packageURL":"pkg:maven/org.http4k/http4k-core","packageIdentity":{"ecosystem":"Maven","name":"org.http4k:http4k-core"},"cpes":[],"source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2026-100724"}],"remediation":[],"references":["https://github.com/http4k/http4k/security/advisories/GHSA-jrpc-7vxp-69p6","https://github.com/http4k/http4k/commit/0121b05537","https://github.com/http4k/http4k/commit/54c6385615","https://www.vulncheck.com/advisories/http4k-before-6.49.0.0-host-header-routing-bypass-via-reverseproxy"],"sources":[{"name":"CVE","id":"CVE-2026-100724","modified":"2026-10-29T21:15:26.111Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-100724"}],"assessments":[{"source":"VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","score":6.3},{"source":"VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N","score":5.4}],"sourceAffected":[],"observedAt":"2026-10-29T21:39:28.414Z","kev":{"status":"not-listed","checkedAt":"2026-10-31T06:30:31.757Z"},"coverage":[{"source":"NVD","status":"available","checkedAt":"2026-10-30T00:30:32.596Z","attemptedAt":"2026-10-30T00:30:32.596Z"},{"source":"GHSA","status":"available","checkedAt":"2026-10-30T00:30:32.929Z","attemptedAt":"2026-10-30T00:30:32.929Z"},{"source":"EUVD","status":"available","checkedAt":"2026-10-30T00:30:32.987Z","attemptedAt":"2026-10-30T00:30:32.987Z"},{"source":"EPSS","status":"available","checkedAt":"2026-10-30T00:30:32.289Z","attemptedAt":"2026-10-30T00:30:32.289Z"}],"evidence":[{"source":"FIRST EPSS","id":"CVE-2026-100724","url":"https://www.first.org/epss/","probability":0.00344,"percentile":0.27883,"date":"2026-10-29","checkedAt":"2026-10-30T00:30:32.289Z"},{"source":"NVD","id":"CVE-2026-100724","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100724","modified":"2026-10-29T21:17:06.847","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","checkedAt":"2026-10-30T00:30:32.596Z"},{"source":"NVD","id":"CVE-2026-100724","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100724","modified":"2026-10-29T21:17:06.847","score":5.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N","checkedAt":"2026-10-30T00:30:32.596Z"},{"source":"GitHub Advisory Database","id":"GHSA-9hc9-gcfq-xg98","url":"https://github.com/advisories/GHSA-9hc9-gcfq-xg98","modified":"2026-09-27T03:31:04Z","score":5.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N","checkedAt":"2026-10-30T00:30:32.929Z"},{"source":"ENISA EUVD","id":"EUVD-2026-87855","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-87855","modified":"Oct 29, 2026, 9:15:26 PM","score":6.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","checkedAt":"2026-10-30T00:30:32.987Z"}],"aiSummary":{"text":"http4k before 6.49.0.0, 5.42.0.0, and 4.51.0.0 has a routing bypass vulnerability via reverseProxy. A remote attacker can supply a Host header containing a configured vhost name to bypass routing-based authorization.","model":"@cf/meta/llama-3.3-70b-instruct-fp8-fast","generatedAt":"2026-10-30T09:40:05.047Z","sources":[{"name":"CVE","url":"https://www.cve.org/CVERecord?id=CVE-2026-100724"}]}}