{"id":"CVE-2026-81894","aliases":["EUVD-2026-78833","GHSA-qgxh-7qc6-mgwq"],"status":"published","title":"Concrete CMS 9.5.2 and below is vulnerable to Stored DOM-based Cross-site Scripting (XSS) in the Gallery block image Caption field","description":"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-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.","severity":{"version":"4.0","score":8.5,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00237,"percentile":0.14888,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-79","CWE-89"],"published":"2026-09-15T16:35:37Z","modified":"2026-11-11T02:31:01Z","products":[{"vendor":"concrete cms","product":"concrete cms"},{"vendor":"concretecms","product":"concrete_cms"}],"references":[{"url":"https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes","tags":["release-notes","Broken Link","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81894","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-qgxh-7qc6-mgwq"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81894.json","tags":["advisory"]},{"url":"https://github.com/concretecms/concretecms","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-81894","title":"Concrete CMS 9.5.2 and below is vulnerable to Stored DOM-based Cross-site Scripting (XSS) in the Gallery block image Caption field","description":"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-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.","status":"published","published":"2026-09-15T16:35:37.767Z","modified":"2026-09-22T18:07:28.458Z","cvss":[{"version":"4.0","score":8.5,"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","level":"high","assessor":"cna"}],"cwes":["CWE-89"],"updated_at":"2026-11-02T13:36:18.075535Z"}],"euvd":[{"id":"EUVD-2026-78833","description":"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-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.","status":"published","published":"2026-09-15T16:35:37Z","modified":"2026-09-22T18:07:28Z","cvss":[{"version":"4.0","score":8.5,"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","level":"high"}],"updated_at":"2026-11-02T17:28:02.149692Z"}],"ghsa":[{"id":"GHSA-qgxh-7qc6-mgwq","title":"Concrete CMS 9.5.2 and below is vulnerable to stored DOM-based Cross-site Scripting (XSS) via the...","description":"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-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.","status":"published","published":"2026-09-15T18:32:33Z","modified":"2026-09-18T21:31:57Z","cvss":[{"version":"4.0","score":8.5,"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/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","level":"high"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-79","CWE-89"],"updated_at":"2026-11-02T15:12:12.006795Z"}],"nvd":[{"id":"CVE-2026-81894","description":"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-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.","status":"published","published":"2026-09-15T17:17:27.543Z","modified":"2026-09-22T19:16:52.367Z","cvss":[{"version":"4.0","score":8.5,"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/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","level":"high","assessor":"secondary"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-89","CWE-79"],"updated_at":"2026-11-02T14:12:47.668237Z"}],"osv":[{"id":"CVE-2026-81894","title":"Concrete CMS 9.5.2 and below is vulnerable to Stored DOM-based Cross-site Scripting (XSS) in the Gallery block image Caption field","description":"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-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.","status":"published","published":"2026-09-15T16:35:37.767Z","modified":"2026-11-11T02:31:01.326740395Z","cvss":[{"version":"4.0","score":8.5,"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","level":"high"}],"cwes":["CWE-89"],"updated_at":"2026-11-11T11:06:53.302002Z"}]}}