{"id":"CVE-2020-26291","aliases":["GHSA-3329-pjwv-fjpg"],"url":"https://o3.security/vulnerability/CVE-2020-26291","summary":"Hostname spoofing via backslashes in URL","details":"URI.js is a javascript URL mutation library (npm package urijs). In URI.js before version 1.19.4, the hostname can be spoofed by using a backslash (`\\`) character followed by an at (`@`) character. If the hostname is used in security decisions, the decision may be incorrect. Depending on library usage and attacker intent, impacts may include allow/block list bypasses, SSRF attacks, open redirects, or other undesired behavior. For example the URL `https://expected-example.com\\@observed-example.com` will incorrectly return `observed-example.com` if using an affected version. Patched versions correctly return `expected-example.com`. Patched versions match the behavior of other parsers which implement the WHATWG URL specification, including web browsers and Node's built-in URL class. Version 1.19.4 is patched against all known payload variants. Version 1.19.3 has a partial patch but is still vulnerable to a payload variant.]","published":"2020-12-31T00:15:12.327Z","modified":"2026-07-09T01:31:06.877809Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"urijs","fixedVersion":"1.19.4"}],"fix":{"url":"https://github.com/medialize/URI.js/commit/b02bf037c99ac9316b77ff8bfd840e90becf1155","label":"medialize/URI.js@b02bf03"},"references":[{"type":"ADVISORY","url":"https://github.com/medialize/URI.js/releases/tag/v1.19.4"},{"type":"ADVISORY","url":"https://github.com/medialize/URI.js/security/advisories/GHSA-3329-pjwv-fjpg"},{"type":"ADVISORY","url":"https://www.npmjs.com/package/urijs"},{"type":"FIX","url":"https://github.com/medialize/URI.js/commit/b02bf037c99ac9316b77ff8bfd840e90becf1155"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T01:31:06.877809Z"}}