{"cve":"CVE-2026-75931","nvd":{"published":"2026-08-24T10:16:40.113","modified":"2026-10-14T13:10:00.187","status":"Analyzed","description":"fast-uri is a URI parser for Node.js. It canonicalizes a host to its ASCII form only when the input carries an explicit scheme, so a scheme-relative reference such as a host preceded by two slashes is returned with its host verbatim and no error set. As a result fast-uri's own entry points disagree with each other: parse, resolve, normalize, and equal can yield different hosts for the same input depending only on whether a scheme is written out, and equal can return opposite verdicts for the same pair of hosts. An application that extracts a host with fast-uri to check it against a policy list and then resolves the same reference can make its decision on one host while the destination is another, enabling host confusion and policy bypass. The affected versions are 2.4.2 up to but not including 2.4.5, 3.1.3 up to but not including 3.1.6, and 4.0.1 up to but not including 4.1.3. The issue is fixed in 2.4.5, 3.1.6, and 4.1.3, which canonicalize the host consistently across the resolve path. Users should upgrade to a patched version.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":["CWE-436"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/fastify/fast-uri/security/advisories/GHSA-5jgf-p345-68v8"],"products":["openjsf:fast-uri"],"source":"nvd","synced_at":"2026-10-19T22:49:38.260478770+00:00"},"epss":{"cve":"CVE-2026-75931","score":0.00398,"percentile":0.33746,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-5jgf-p345-68v8","url":"https://osv.dev/vulnerability/GHSA-5jgf-p345-68v8","summary":"fast-uri vulnerable to host confusion via skipped IDN canonicalization on scheme-relative references","modified":"2026-09-10T03:51:15.083681721Z","packages":[{"ecosystem":"npm","name":"fast-uri","purl":"pkg:npm/fast-uri","ranges":[">=2.4.2 <2.4.5"],"fixed":["2.4.5"]},{"ecosystem":"npm","name":"fast-uri","purl":"pkg:npm/fast-uri","ranges":[">=3.1.3 <3.1.6"],"fixed":["3.1.6"]},{"ecosystem":"npm","name":"fast-uri","purl":"pkg:npm/fast-uri","ranges":[">=4.0.1 <4.1.3"],"fixed":["4.1.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}