{"cve":"CVE-2026-41591","nvd":{"published":"2026-05-08T16:16:11.167","modified":"2026-08-26T19:16:01.883","status":"Analyzed","description":"Marko is a declarative, HTML-based language for building web apps. Prior to marko version 5.38.36 and prior to @marko/runtime-tags 6.0.164, when dynamic text is interpolated into a <script> or <style> tag the Marko runtime failed to prevent tag breakout when the closing tag used non-lowercase casing. An attacker able to place input inside a <script> or <style> block could break out of the tag with </SCRIPT>, </Style>, etc. and inject arbitrary HTML/JavaScript, resulting in cross-site scripting. This issue has been patched in marko version 5.38.36 and @marko/runtime-tags 6.0.164.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N","score":6.4},"cwes":["CWE-79"],"references":["https://github.com/marko-js/marko/security/advisories/GHSA-x9fj-57fh-c8wq","https://github.com/marko-js/marko/security/advisories/GHSA-x9fj-57fh-c8wq"],"products":["openjsf:marko","openjsf:marko\\/runtime-tags"],"source":"nvd","synced_at":"2026-10-19T22:33:55.586217763+00:00"},"epss":{"cve":"CVE-2026-41591","score":0.00227,"percentile":0.13447,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-x9fj-57fh-c8wq","url":"https://osv.dev/vulnerability/GHSA-x9fj-57fh-c8wq","summary":"Marko: XSS via case-insensitive script/style closing tag bypass in runtime HTML escaping","modified":"2026-05-13T13:54:56.772894Z","packages":[{"ecosystem":"npm","name":"marko","purl":"pkg:npm/marko","ranges":["<5.38.36"],"fixed":["5.38.36"]},{"ecosystem":"npm","name":"@marko/runtime-tags","purl":"pkg:npm/%40marko/runtime-tags","ranges":["<6.0.164"],"fixed":["6.0.164"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}