{"id":"GHSA-373m-p57p-8665","summary":"Duplicate Advisory: Grav: XSS Blueprint Validation Bypass via Twig String Concatenation","details":"### Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-2c4f-86xc-cr74. This link is maintained to preserve external references.\n\n### Original Description\nGrav v2.0.0 contains a cross-site scripting vulnerability (fixed in 2.0.1). The XSS blueprint validator (Security::detectXss()) runs on raw page content before Twig processing. When Twig content processing is enabled (twig_content.process_enabled: true), an attacker with page-write API permission can use Twig's string concatenation operator (~) to dynamically construct event handler names, dangerous tag names, or dangerous protocols at render time (e.g. {% set x = \"on\" ~ \"error\" %}). The validator sees only the harmless Twig expression and allows the content, but after Twig rendering the output (rendered via {{ page.content|raw }}) contains an active payload such as \u003cimg src=1 onerror=alert(1)\u003e, executing arbitrary JavaScript in visitors' browsers.","modified":"2026-09-16T22:30:08.124104469Z","published":"2026-07-15T12:32:04Z","withdrawn":"2026-09-16T22:13:08Z","database_specific":{"cwe_ids":["CWE-79"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-09-16T22:13:08Z","nvd_published_at":"2026-07-15T12:18:20Z"},"references":[{"type":"WEB","url":"https://github.com/getgrav/grav/security/advisories/GHSA-2c4f-86xc-cr74"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-61453"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/grav-before-xss-via-twig-string-concatenation"}],"affected":[{"package":{"name":"getgrav/grav","ecosystem":"Packagist","purl":"pkg:composer/getgrav/grav"},"versions":["2.0.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-373m-p57p-8665/GHSA-373m-p57p-8665.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}