{"id":"CVE-2018-20583","aliases":["GHSA-qx76-c53f-5c7q"],"url":"https://o3.security/vulnerability/CVE-2018-20583","summary":"PHP League CommonMark vulnerable to Cross-Site Scripting (XSS)","details":"Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library versions 0.15.6 through 0.18.x before 0.18.1 allows remote attackers to insert unsafe URLs into HTML (even if allow_unsafe_links is false) via a newline character (e.g., writing javascript as javascri%0apt).","published":"2018-12-30T05:29:00.753Z","modified":"2026-10-20T10:50:07.634258507Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"Packagist","name":"league/commonmark","fixedVersion":"0.18.1"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://commonmark.thephpleague.com/changelog/"},{"type":"ADVISORY","url":"https://github.com/thephpleague/commonmark/releases/tag/0.18.1"},{"type":"EVIDENCE","url":"https://github.com/thephpleague/commonmark/issues/337"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2018-20583"},{"type":"WEB","url":"https://commonmark.thephpleague.com/changelog"},{"type":"WEB","url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/league/commonmark/CVE-2018-20583.yaml"},{"type":"PACKAGE","url":"https://github.com/thephpleague/commonmark"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-20T10:50:07.634258507Z"}}