{"id":"CVE-2026-81894","title":"Concrete CMS 9.5.2 and below is vulnerable to stored DOM-based Cross-site Scripting (XSS) via the Gallery block's per-image Caption field because the bundled Magnific Popup lightbox script (concrete/js/features/imagery/frontend.js) re-pa…","summary":"Concrete CMS 9.5.2 and below is vulnerable to stored DOM-based Cross-site Scripting (XSS) via the Gallery block's per-image Caption field because the bundled Magnific Popup lightbox script (concrete/js/features/imagery/frontend.js) re-pa…","severity":"medium","cvss":5.4,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","cwe":["CWE-89","CWE-79"],"vendor":"concretecms","product":"concrete_cms","affected":["concrete_cms < 9.5.3"],"patched":["concrete_cms 9.5.3"],"published":"2026-09-15","updated":"2026-09-22","sourceUpdated":"2026-09-22T19:16:52.367","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-81894","references":[{"url":"https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes","label":"ff5b8ace-8b95-4078-9743-eac1ca5451de"}],"tags":["nvd","cve.org","score-dispute"],"epss":0.0014,"epssPercentile":0.03691,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-22T18:05:47.459277Z"},"scores":{"nvd":5.4,"cna":8.5},"ingestedAt":"2026-09-15T17:41:02.865Z","slug":"CVE-2026-81894","body":"## Overview\n\nConcrete CMS 9.5.2 and below is vulnerable to stored DOM-based Cross-site Scripting (XSS) via the Gallery block's per-image Caption field because the bundled Magnific Popup lightbox script (concrete/js/features/imagery/frontend.js) re-parses the attribute-decoded caption as HTML through jQuery's .append() in titleSrc instead of inserting it as text. A user with permission to edit a page containing a Gallery block can store a caption that executes in the browser of any visitor who opens that image's lightbox. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 8.5 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting.\n\n## Affected\n\n- `concrete_cms < 9.5.3`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `concrete_cms 9.5.3`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":29.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":207470,"id":"CVE-2026-81894","ts":1789761021590,"field":"cvss","old":"8.5","new":"5.4"},{"seq":207469,"id":"CVE-2026-81894","ts":1789761021590,"field":"severity","old":"high","new":"medium"}]}