CVE-2026-3643 [High]

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-05-17	0.08%	0.18%	+0.10%
2	2026-04-15	—	0.08%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-05-17

0.08%

0.18%

+0.10%

2026-04-15

—

0.08%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.2	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	3.9	2.7	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.2

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

3.9

2.7

[email protected]

Affected software / configurations for CVE-2026-3643

Vendor	Product	Version	Raw CPE
No affected products in dataset.

References for CVE-2026-3643

URL	Tags
https://plugins.trac.wordpress.org/browser/otm-accessibly/tags/3.0.3/public/Api/BaseApiController.php#L22
https://plugins.trac.wordpress.org/browser/otm-accessibly/tags/3.0.3/public/AssetsManager.php#L63
https://plugins.trac.wordpress.org/browser/otm-accessibly/tags/3.0.3/public/Data/AccessiblyOptions.php#L69
https://plugins.trac.wordpress.org/browser/otm-accessibly/tags/3.0.3/public/admin/AdminApi.php#L65
https://plugins.trac.wordpress.org/browser/otm-accessibly/trunk/public/Api/BaseApiController.php#L22
https://plugins.trac.wordpress.org/browser/otm-accessibly/trunk/public/AssetsManager.php#L63
https://plugins.trac.wordpress.org/browser/otm-accessibly/trunk/public/Data/AccessiblyOptions.php#L69
https://plugins.trac.wordpress.org/browser/otm-accessibly/trunk/public/admin/AdminApi.php#L65
https://www.wordfence.com/threat-intel/vulnerabilities/id/f8234ea2-ff80-425f-b83d-29c422b40c6a?source=cve

URL

CVE-2026-3643 | Accessibly <= 3.0.3 - Missing Authorization to Unauthenticated Stored Cross-Site Scripting via Widget Source Injection via REST API

Exploit prediction scoring system (EPSS) score for CVE-2026-3643

Common vulnerability scoring system (CVSS) metrics for CVE-2026-3643

Weakness enumeration for CVE-2026-3643

GitHub Security Advisory for CVE-2026-3643

Affected software / configurations for CVE-2026-3643

References for CVE-2026-3643