Craft CMS up to 4.17.0-beta.0/5.9.0-beta.0 Setting cross site scripting

Summaryinfo

A vulnerability described as problematic has been identified in Craft CMS up to 4.17.0-beta.0/5.9.0-beta.0. Affected by this vulnerability is an unknown functionality of the component Setting Handler. The manipulation results in cross site scripting. This vulnerability is identified as CVE-2026-56393. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic has been found in Craft CMS up to 4.17.0-beta.0/5.9.0-beta.0. Affected is an unknown code block of the component Setting Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

Craft CMS 4.x (>= 4.0.0-RC1, = 5.0.0-RC1, < 5.9.0-beta.1) contain multiple stored cross-site scripting vulnerabilities where settings names and field option labels are rendered without sanitization (e.g., via the checkbox.twig template, which used {{ label|raw }}). An authenticated administrator (with allowAdminChanges enabled) can inject malicious payloads into section names, volume names, user group names, global set names, generated field names, checkbox/radio option labels, and custom source labels, causing arbitrary JavaScript to execute in other users' control-panel sessions. Fixed in 4.17.0-beta.1 and 5.9.0-beta.1.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-56393 since 06/21/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation needs additional levels of successful authentication. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 4.17.0-beta.1 or 5.9.0-beta.1 eliminates this vulnerability. Applying the patch 67780a778c6ec04e68e64a0b1177c168306144a2 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-38159). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Content Management System

Vendor

• Craft

Name

• CMS

Version

• 4.17.0-beta
• 5.9.0-beta

License

• free

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Once again VulDB remains the best source for vulnerability data.

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