CVE-2026-41591: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in marko-js marko
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.
AI Analysis
Technical Summary
Marko is an HTML-based language for building web applications. Before marko version 5.38.36 and @marko/runtime-tags 6.0.164, the runtime failed to properly neutralize input when dynamic text was inserted inside <script> or <style> tags if the closing tag was not in lowercase (e.g., </SCRIPT>, </Style>). This allowed attackers who could inject input within these tags to break out of the tag context and inject arbitrary HTML or JavaScript, resulting in a cross-site scripting vulnerability (CWE-79). The issue has been fixed in the specified patched versions.
Potential Impact
Successful exploitation allows an attacker with the ability to place input inside <script> or <style> tags to execute arbitrary HTML or JavaScript in the context of the vulnerable web application. This can lead to partial compromise of confidentiality and integrity (as per CVSS: low confidentiality and integrity impact) but does not affect availability. The vulnerability requires network access and low complexity with no user interaction, and privileges are required to inject the malicious input.
Mitigation Recommendations
This vulnerability is patched in marko version 5.38.36 and @marko/runtime-tags version 6.0.164. Users of affected versions should upgrade to these or later versions to remediate the issue. Patch status is confirmed by the vendor advisory stating the fix is included in these releases. No additional mitigation steps are indicated.
CVE-2026-41591: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in marko-js marko
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Marko is an HTML-based language for building web applications. Before marko version 5.38.36 and @marko/runtime-tags 6.0.164, the runtime failed to properly neutralize input when dynamic text was inserted inside <script> or <style> tags if the closing tag was not in lowercase (e.g., </SCRIPT>, </Style>). This allowed attackers who could inject input within these tags to break out of the tag context and inject arbitrary HTML or JavaScript, resulting in a cross-site scripting vulnerability (CWE-79). The issue has been fixed in the specified patched versions.
Potential Impact
Successful exploitation allows an attacker with the ability to place input inside <script> or <style> tags to execute arbitrary HTML or JavaScript in the context of the vulnerable web application. This can lead to partial compromise of confidentiality and integrity (as per CVSS: low confidentiality and integrity impact) but does not affect availability. The vulnerability requires network access and low complexity with no user interaction, and privileges are required to inject the malicious input.
Mitigation Recommendations
This vulnerability is patched in marko version 5.38.36 and @marko/runtime-tags version 6.0.164. Users of affected versions should upgrade to these or later versions to remediate the issue. Patch status is confirmed by the vendor advisory stating the fix is included in these releases. No additional mitigation steps are indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-21T14:15:21.960Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69fe067ecbff5d8610f6728e
Added to database: 5/8/2026, 3:51:26 PM
Last enriched: 5/8/2026, 4:07:44 PM
Last updated: 5/8/2026, 9:56:35 PM
Views: 4
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