Summary
CVE-2026-54848 is a high-severity Insertion of Sensitive Information Into Sent Data vulnerability (CWE-201) in the APIExperts Square for WooCommerce WordPress plugin — also marketed as WC Shop Sync — affecting all versions through 4.7.3. The flaw enables unauthenticated remote attackers to retrieve sensitive data embedded in HTTP responses without any privileges or user interaction, earning a CVSS v3.1 base score of 8.3 (HIGH) with Scope Changed, meaning the impact crosses component boundaries beyond the plugin itself. A patched version (4.7.4) has been released.
Technical details
- Root cause: CWE-201 (Insertion of Sensitive Information Into Sent Data) — the plugin inadvertently includes sensitive information within HTTP response data, making it retrievable by unauthenticated external parties. The associated attack pattern is CAPEC-37 (Retrieve Embedded Sensitive Data).
- Trigger conditions: No authentication is required and no user interaction is needed; any unauthenticated network request can trigger the exposure condition.
- Attack vector: Network-accessible (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N).
- Impact: The Scope Changed metric (S:C) indicates the impact extends beyond the plugin component itself. This plugin acts as the integration layer between WooCommerce and the Square payment platform — handling Square API credentials, OAuth tokens, payment configuration, customer data, and order synchronization. Unauthorized retrieval of such data could enable access to the connected Square merchant account, with potential downstream consequences including unauthorized payment operations or financial data exposure.
Affected software
- APIExperts Square for WooCommerce (WordPress plugin slug:
woosquare, also branded "WC Shop Sync") — all versions from the beginning through and including 4.7.3
Severity
- CVSS v3.1 Base Score: 8.3 (HIGH)
- Vector String:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
Mitigation and recommended actions
- Immediate action: Update to version 4.7.4 or later. Version 4.7.4, released May 22, 2026, addresses this vulnerability with enhanced security measures, as documented in the plugin’s official changelog on WordPress.org.
- If immediate patching is not possible: Restrict external network access to the affected WordPress installation at the perimeter level until the plugin can be updated. Consider temporarily deactivating the plugin if Square payment processing can be suspended without business impact.
IONIX Status
The IONIX research team is tracking ongoing exploitation attempts and recommends immediate patching. Potentially affected assets are outlined in this post.

