Cross-site Scripting when rendering error messages in laminas-form
Date: 2022-01
Affected: composer/laminas/laminas-form, composer/laminas/laminas-form, composer/laminas/laminas-form
Attack vector: xss
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2022-23598
CWE: CWE-79
CVSS: 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)

### Impact When rendering validation error messages via the `formElementErrors()` view helper shipped with laminas-form, many messages will contain the submitted value. However, in vulnerable versions of laminas-form, the value was not being escaped for HTML contexts, which can potentially lead to a Reflected Cross-Site Scripting (XSS) attack. ### Patches The following versions were issued to mitigate the vulnerability: - 2.17.1 - 3.0.2 - 3.1.1 ### Workarounds At the top of a view script where you call the `formElementErrors()` view helper, place the following code: ```php use Laminas\Form\ElementInterface; use Laminas\View\PhpRenderer; $escapeMessages = function (ElementInterface $formOrElement, PhpRenderer $renderer): void { $messages = $element->getMessages(); if (! $messages) { return; } $escaped = []; array_walk_recursive( $messages, static function (string $item) use (&$escaped, $renderer): void { $escaped[] = $renderer->escapeHtml($item); } }; $element->setMessages($escaped); }; ``` Before calling `formElementErrors()` with a form, fieldset, or element, call the above closure as follows ```php // Usage with a form // $this is the view renderer $escapeMessages($form, $this); // Usage with a fieldset // $this is the view renderer $escapeMessages($fieldset, $this); // Usage with a form element // $this is the view renderer $escapeMessages($element, $this); ``` ### For more information


Mitigations:

Architectural layers (MAESTRO):