{"id":"CVE-2026-86205","summary":"h3 before 2.0.1-rc.18 Open Redirect via redirectBack()","details":"h3 versions before 2.0.1-rc.18 contain an open redirect vulnerability in the redirectBack() utility that fails to sanitize protocol-relative paths in the Referer header pathname. Attackers can craft a same-origin URL with a double-slash path segment that passes origin validation but produces a Location header interpreted by browsers as a protocol-relative redirect to an external domain.","aliases":["GHSA-fp4x-ggrf-wmc6"],"modified":"2026-09-10T03:30:21.961594181Z","published":"2026-09-06T12:00:25.530Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86205.json","cna_assigner":"VulnCheck","cwe_ids":["CWE-601"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86205.json"},{"type":"ADVISORY","url":"https://github.com/h3js/h3/security/advisories/GHSA-fp4x-ggrf-wmc6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86205"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/h3-before-2.0.1-rc.18-open-redirect-via-redirectback"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/h3js/h3","events":[{"introduced":"388b8f06e060a219d11bbc6be7f70f38d8bbea01"},{"fixed":"cb70e1ba513be827bb3698127bb7d06467412911"}],"database_specific":{"extracted_events":[{"introduced":"2.0.1-rc.17"},{"fixed":"2.0.1-rc.18"},{"introduced":"0"}],"source":["AFFECTED_FIELD","DESCRIPTION"]}}],"versions":["v2.0.1-rc.17"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-86205.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"}]}