CVE-2026-31823

Workarounds

Override vulnerable templates and JavaScript controllers at the project level.

Step 1, Override shop breadcrumbs template

templates/bundles/SyliusShopBundle/shared/breadcrumbs.html.twig:

{% macro breadcrumbs(items) %}
    <ol class="breadcrumb" aria-label="breadcrumbs">
        {% for item in items %}
            <li class="breadcrumb-item fw-normal{{ item.active is defined and item.active ? ' active' }}">
                {% if item.path is defined %}
                    <a class="link-reset" href="{{ item.path }}" {{ item.test_attribute is defined ? sylius_test_html_attribute(item.test_attribute) }}>{{ item.label }}</a>
                {% else %}
                    <span class="text-body-tertiary text-break" {{ item.test_attribute is defined ? sylius_test_html_attribute(item.test_attribute) }}>{{ item.label }}</span>
                {% endif %}
            </li>
        {% endfor %}
    </ol>
{% endmacro %}

Step 2, Override order breadcrumbs template

templates/bundles/SyliusShopBundle/account/order/show/content/breadcrumbs.html.twig:

{% from '@SyliusShop/shared/breadcrumbs.html.twig' import breadcrumbs as breadcrumbs %}

{% set order = hookable_metadata.context.order %}

<div class="col-12">
    {{ breadcrumbs([
        { label: 'sylius.ui.home'|trans, path: path('sylius_shop_homepage')},
        { label: 'sylius.ui.my_account'|trans, path: path('sylius_shop_account_dashboard')},
        { label: 'sylius.ui.order_history'|trans, path: path('sylius_shop_account_order_index')},
        { label: '#'~order.number, active: true, test_attribute: 'order-number' }
    ]) }}
</div>

Step 3, Override ProductTaxonTreeController.js

Disable the vendor controller in assets/admin/controllers.json:

  "product-taxon-tree": {
-   "enabled": true,
+   "enabled": false,
    "fetch": "lazy"
  },

Create assets/admin/controllers/product_taxon_tree_controller.js, copy the original from vendor/sylius/sylius/src/Sylius/Bundle/AdminBundle/Resources/assets/controllers/ProductTaxonTreeController.js and apply the following change:

+ const escapeHtml = (str) => {
+     const div = document.createElement('div');
+     div.textContent = str;
+     return div.innerHTML;
+ };

  // in rowRenderer:
- <span class="infinite-tree-title">${name}</span>
+ <span class="infinite-tree-title">${escapeHtml(name)}</span>

Register the patched controller in assets/admin/bootstrap.js:

import ProductTaxonTreeController from './controllers/product_taxon_tree_controller';
app.register('sylius--admin-bundle--product-taxon-tree', ProductTaxonTreeController);

Step 4, Add autocomplete XSS protection

assets/admin/scripts/autocomplete-xss-protection.js:

const escapeHtml = (str) => {
    if (typeof str !== 'string') return str;
    const div = document.createElement('div');
    div.textContent = str;
    return div.innerHTML;
};

document.addEventListener('autocomplete:pre-connect', (event) => {
    const options = event.detail.options;
    if (!options.render) return;

    const labelField = options.labelField || 'text';
    const wrapRenderer = (renderer) => {
        if (!renderer) return renderer;
        return (data, escape) => {
            const escaped = { ...data };
            if (escaped[labelField]) {
                escaped[labelField] = escapeHtml(escaped[labelField]);
            }
            return renderer(escaped, escape);
        };
    };

    if (options.render.item) options.render.item = wrapRenderer(options.render.item);
    if (options.render.option) options.render.option = wrapRenderer(options.render.option);
});

Import in assets/admin/entrypoint.js before bootstrap:

+ import './scripts/autocomplete-xss-protection';
  import './bootstrap.js';

Step 5, Rebuild assets

yarn encore dev  # or: yarn encore production

Reporters

We would like to extend our gratitude to the following individuals for their detailed reporting and responsible disclosure of this vulnerability:

• Djibril Mounkoro (@whiteov3rflow)
• Bartłomiej Nowiński (@bnBart)

For more information

If you have any questions or comments about this advisory:

• Open an issue in Sylius issues
• Email us at [email protected]

An authenticated stored cross-site scripting (XSS) vulnerability exists in multiple places across the shop frontend and admin panel due to unsanitized entity names being rendered as raw HTML.

Shop breadcrumbs (shared/breadcrumbs.html.twig): The breadcrumbs macro uses the Twig |raw filter on label values. Since taxon names, product names, and ancestor names flow directly into these labels, a malicious taxon name like <img src=x onerror=alert('XSS')> is rendered and executed as JavaScript on the storefront.

Admin product taxon picker (ProductTaxonTreeController.js): The rowRenderer method interpolates ${name} directly into a template literal building HTML, allowing script injection through taxon names in the admin panel.

Admin autocomplete fields (Tom Select): Dropdown items and options render entity names as raw HTML without escaping, allowing XSS through any autocomplete field displaying entity names.

An authenticated administrator can inject arbitrary HTML or JavaScript via entity names (e.g. taxon name) that is persistently rendered for all users.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2026-31823 has a CVSS score of 4.8 (Medium). The vector is network-reachable, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.0.16, 2.1.12, 2.2.3); upgrading removes the vulnerable code path.

Kodem intelligence

The issue is fixed in versions: 2.0.16, 2.1.12, 2.2.3 and above.

1. What is CVE-2026-31823? CVE-2026-31823 is a medium-severity cross-site scripting (XSS) vulnerability in sylius/sylius (composer), affecting versions >= 2.0.0, <= 2.0.15. It is fixed in 2.0.16, 2.1.12, 2.2.3. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2026-31823? CVE-2026-31823 has a CVSS score of 4.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of sylius/sylius are affected by CVE-2026-31823? sylius/sylius (composer) versions >= 2.0.0, <= 2.0.15 is affected.
4. Is there a fix for CVE-2026-31823? Yes. CVE-2026-31823 is fixed in 2.0.16, 2.1.12, 2.2.3. Upgrade to this version or later.
5. Is CVE-2026-31823 exploitable, and should I be worried? Whether CVE-2026-31823 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-31823 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-31823?
   • Upgrade sylius/sylius to 2.0.16 or later
   • Upgrade sylius/sylius to 2.1.12 or later
   • Upgrade sylius/sylius to 2.2.3 or later