{"schema":"threatline.record/2","record":{"id":"CVE-2026-86472","aliases":["GHSA-hrr3-gc8f-f4qj"],"summary":"fast-uri vulnerable to inconsistent host case normalization via percent-encoded octets","details":"### Impact\n\n`fast-uri` folds the host to lowercase before it percent-decodes the host, so a percent-encoded uppercase unreserved octet such as `%41` decodes to a literal `A` that is never folded. For a scheme-relative reference (`//host`) there is no scheme, so the host canonicalization that repairs this on a scheme-bearing URL does not run. As a result `parse`, `normalize`, and `equal` disagree on the same host: `parse(\"//%41.com\").host` returns `\"A.com\"` while `parse(\"//a.com\").host` and `parse(\"//A.com\").host` return `\"a.com\"`, and `equal(\"//%41.com\", \"//a.com\")` is `false` even though `equal(\"//A.com\", \"//a.com\")` is `true`. An application that makes a case-sensitive host decision on `fast-uri` output for a scheme-relative reference, for example a host allowlist or denylist that compares `parse(url).host` or uses `fast-uri.equal`, can be steered past the check with a percent-encoded uppercase octet. Because a hostname is case-insensitive in DNS and HTTP routing, the evading spelling reaches the same host the check meant to gate, so the effect is check evasion rather than reaching a different registrable host.\n\n### Patches\n\nUpgrade to `fast-uri` 4.1.5, 3.1.8, or 2.4.7.\n\n### Workarounds\n\nCompare hosts case-insensitively (lowercase the parsed host before any allowlist or denylist decision), or avoid making case-sensitive host decisions on scheme-relative input until upgrading.","categories":["Libraries & packages"],"product":"fast-uri","vendor":"fast-uri","ecosystem":"npm","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-29T23:54:26Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"fast-uri"},"range":"< 2.4.7"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-29T23:54:26Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"fast-uri"},"range":">= 3.0.0, < 3.1.8"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-29T23:54:26Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"fast-uri"},"range":">= 4.0.0, < 4.1.5"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-86472","source_modified_at":"2026-09-15T12:35:44.789Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"fast-uri","vendor":"fast-uri","versions":[{"versionType":"semver","status":"affected","version":"0","lessThan":"2.4.7"},{"versionType":"semver","status":"unaffected","version":"2.4.7"},{"versionType":"semver","status":"affected","version":"3.0.0","lessThan":"3.1.8"},{"versionType":"semver","status":"unaffected","version":"3.1.8"},{"versionType":"semver","status":"affected","version":"4.0.0","lessThan":"4.1.5"},{"versionType":"semver","status":"unaffected","version":"4.1.5"}],"defaultStatus":"unaffected"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-30T00:00:04.426165475Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.4.7"}]}],"versions":[]},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-30T00:00:04.426165475Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"3.0.0"},{"fixed":"3.1.8"}]}],"versions":[]},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-30T00:00:04.426165475Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"ranges":[{"type":"SEMVER","events":[{"introduced":"4.0.0"},{"fixed":"4.1.5"}]}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-29T23:54:26Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"fast-uri"},"version":"2.4.7"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-29T23:54:26Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"fast-uri"},"version":"3.1.8"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-29T23:54:26Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"fast-uri"},"version":"4.1.5"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-86472","source_modified_at":"2026-09-15T12:35:44.789Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":null},"version":"2.4.7","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-86472","source_modified_at":"2026-09-15T12:35:44.789Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":null},"version":"3.1.8","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-86472","source_modified_at":"2026-09-15T12:35:44.789Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":null},"version":"4.1.5","basis":"first unaffected version stated in the CVE record"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-30T00:00:04.426165475Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"version":"2.4.7"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-30T00:00:04.426165475Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"version":"3.1.8"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-hrr3-gc8f-f4qj","source_modified_at":"2026-09-30T00:00:04.426165475Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"fast-uri","ecosystem":"npm","purl":"pkg:npm/fast-uri"},"version":"4.1.5"}],"cvss":4.8,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00253,"percentile":0.1584,"score_date":"2026-10-23"},"published_at":"2026-09-15T10:29:50.594Z","modified_at":"2026-09-30T00:00:04.426165475Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-hrr3-gc8f-f4qj","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-09-29T23:54:26Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-86472","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-09-15T12:35:44.789Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-hrr3-gc8f-f4qj","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-09-30T00:00:04.426165475Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-86472","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["GitHub Advisory Database","CVE List","OSV","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/fastify/fast-uri/security/advisories/GHSA-hrr3-gc8f-f4qj"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86472","source":"GitHub Advisory Database"},{"url":"https://github.com/fastify/fast-uri/commit/5dabb86732aa2a7655e258719970e61e12b6b4d1","source":"GitHub Advisory Database"},{"source":"CVE List","url":"https://cna.openjsf.org/security-advisories.html"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v2.4.7","source":"GitHub Advisory Database"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v3.1.8","source":"GitHub Advisory Database"},{"url":"https://github.com/fastify/fast-uri/releases/tag/v4.1.5","source":"GitHub Advisory Database"},{"url":"https://github.com/advisories/GHSA-hrr3-gc8f-f4qj","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"partial","assessed_at":"2026-09-15T12:35:19.770627Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-09-30T00:00:04.426165475Z","content_hash":"9e3170b22d6dfffd63802b09886d8c0780e18a283d0e72a6bf97f74e80313cbc"}}