{"id":"CVE-2026-86251","summary":"h3 before 1.15.9 Path Traversal via Double Decoding","details":"h3 versions before 1.15.9 contain a path traversal vulnerability in the serveStatic utility. A double-decoding flaw allows a request path containing double-encoded dot sequences (e.g. %252e%252e) to be decoded to %2e%2e, which survives resolveDotSegments() because that function only checks for literal '.' characters. When the resulting asset ID is resolved by URL-based backends (CDN, S3, object storage), %2e%2e is interpreted as '..' per RFC 3986, enabling path traversal to read arbitrary files from the backend.","aliases":["GHSA-72gr-qfp7-vwhw"],"modified":"2026-09-11T03:30:31.777159918Z","published":"2026-09-06T12:00:26.881Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86251.json","cna_assigner":"VulnCheck","cwe_ids":["CWE-22"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86251.json"},{"type":"ADVISORY","url":"https://github.com/h3js/h3/security/advisories/GHSA-72gr-qfp7-vwhw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86251"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/h3-before-1.15.9-path-traversal-via-double-decoding"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/h3js/h3","events":[{"introduced":"0"},{"fixed":"4e8d43a7703d0d5c8bbc09748db1d8b9f3c51b42"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"1.15.9"}],"source":["AFFECTED_FIELD","DESCRIPTION"]}}],"versions":["v1.15.7","v1.15.6","v1.15.5","v1.15.4","v1.15.2","v1.15.1","v1.15.0","v1.14.0","v1.13.1","v1.13.0","v1.12.0","v1.11.1","v1.11.0","v1.10.2","v1.10.1","v1.10.0","v1.9.0","v1.8.2","v1.8.1","v1.8.0","v1.8.0-rc.3","v1.8.0-rc.2","v1.8.0-rc.1","v1.8.0-rc.0","v1.7.1","v1.7.0","v1.6.6","v1.6.5","v1.6.4","v1.6.3","v1.6.2","v1.6.1","v1.6.0","v1.5.0","v1.4.0","v1.3.0","v1.2.1","v1.2.0","v1.1.0","v1.0.2","v1.0.1","v1.0.0","v0.8.6","v0.8.5","v0.8.4","v0.8.3","v0.8.2","v0.8.1","v0.8.0","v0.7.21","v0.7.20","v0.7.19","v0.7.18","v0.7.17","v0.7.16","v0.7.15","v0.7.14","v0.7.13","v0.7.12","v0.7.11","v0.7.10","v0.7.9","v0.7.8","v0.7.7","v0.7.6","v0.7.5","v0.7.4","v0.7.3","v0.7.2","v0.7.1","v0.7.0","v0.6.0","v0.5.7","v0.5.6","v0.5.5","v0.5.4","v0.5.3","v0.5.2","v0.5.1","v0.5.0","v0.4.2","v0.4.1","v0.4.0","v0.3.9","v0.3.8","v0.3.7","v0.3.6","v0.3.5","v0.3.4","v0.3.3","v0.3.2","v0.3.1","v0.3.0","v0.2.12","v0.2.11","v0.2.10","v0.2.9","v0.2.8","v0.2.7","v0.2.6","v0.2.5","v0.2.4","v0.2.3","v0.2.2","v0.2.1","v0.2.0","v0.0.15","v0.0.14","v0.0.13","v0.0.12","v0.0.11","v0.0.10","v0.0.9","v0.0.8","v0.0.7","v0.0.6","v0.0.5","v0.0.4","v0.0.3","v0.0.2","v0.0.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-86251.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"}]}