CVE-2026-41591
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.
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 6.4 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- EPSS
- 0.23% probability · 13th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Affected
- openjsf/marko · openjsf/marko\/runtime-tags
- Source
- security-advisories@github.com
References
- https://github.com/marko-js/marko/security/advisories/GHSA-x9fj-57fh-c8wqExploit, Mitigation, Patch, Vendor Advisory
- https://github.com/marko-js/marko/security/advisories/GHSA-x9fj-57fh-c8wqExploit, Mitigation, Patch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.