CVE-2026-3643

CVE-2026-3643 is a high-severity vulnerability with a CVSS 3.x base score of 7.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Description

The Accessibly plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the REST API in all versions up to, and including, 3.0.3. The plugin registers REST API endpoints at `/otm-ac/v1/update-widget-options` and `/otm-ac/v1/update-app-config` with the `permission_callback` set to `__return_true`, which means no authentication or authorization check is performed. The `updateWidgetOptions()` function in `AdminApi.php` accepts user-supplied JSON data and passes it directly to `AccessiblyOptions::updateAppConfig()`, which saves it to the WordPress options table via `update_option()` without any sanitization or validation. The stored `widgetSrc` value is later retrieved by `AssetsManager::enqueueFrontendScripts()` and passed directly to `wp_enqueue_script()` as the script URL, causing it to be rendered as a `<script>` tag on every front-end page. This makes it possible for unauthenticated attackers to inject arbitrary JavaScript that executes for all site visitors by changing the `widgetSrc` option to point to a malicious external script.

Frequently asked questions

What is CVE-2026-3643?
The Accessibly plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the REST API in all versions up to, and including, 3.0.3. The plugin registers REST API endpoints at `/otm-ac/v1/update-widget-options` and `/otm-ac/v1/update-app-config` with the `permission_callback` set to `__return_true`, which means no authentication or authorization check is performed. The `updateWidgetOptions()` function in `AdminApi.php` accepts user-supplied JSON data and passes it directly to `AccessiblyOptions::updateAppConfig()`, which saves it to the WordPress options table via `update_option()` without any sanitization or validation. The stored `widgetSrc` value is later retrieved by `AssetsManager::enqueueFrontendScripts()` and passed directly to `wp_enqueue_script()` as the script URL, causing it to be rendered as a `<script>` tag on every front-end page. This makes it possible for unauthenticated attackers to inject arbitrary JavaScript that executes for all site visitors by changing the `widgetSrc` option to point to a malicious external script.
How severe is CVE-2026-3643?
CVE-2026-3643 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-3643 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-3643?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-3643 have an EU (EUVD) identifier?
Yes. CVE-2026-3643 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22860.
When was CVE-2026-3643 published?
CVE-2026-3643 was published on 2026-04-15 and last updated on 2026-06-17.

References

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →