Deserialization of untrusted data in uscnanbu Welcart e-Commerce
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-502.
Summary
The Welcart e-Commerce plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 2.12.1 via deserialization of untrusted input in the Telecom EDY payment callback (usces_action_acting_transaction). Unauthenticated attackers can store arbitrary 'reserve' key/value pairs as order metadata during a public checkout, then invoke the callback with an attacker-chosen 'option' parameter to select and unserialize that metadata without any provider signature, source-address, transaction-identity or ownership check. A POP chain is present in the TCPDF library bundled with the plugin itself, so no additional plugin or theme is required. This makes it possible for unauthenticated attackers to delete arbitrary files on the server, including wp-config.php, which can lead to remote code execution when an attacker re-runs the WordPress installer against a database they control. Successful exploitation is contingent on an admin printing an invoice to trigger file deletion.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-19887
- 2026-10-03 Alias added: GHSA-fq25-6gpx-5vxf
- 2026-10-25 EPSS moved to the 50th–90th percentile
References
Other 10
- https://www.wordfence.com/threat-intel/vulnerabilities/id/716a7c3c-2e26-4da9-a299-7dcbaa7e4895?source=cve
- https://plugins.trac.wordpress.org/browser/usc-e-shop/trunk/functions/hoock_func.php#L517
- https://plugins.trac.wordpress.org/browser/usc-e-shop/trunk/classes/cart.class.php#L546
- https://plugins.trac.wordpress.org/browser/usc-e-shop/trunk/functions/function.php#L218
- https://plugins.trac.wordpress.org/browser/usc-e-shop/trunk/classes/orderData.class.php#L41
- https://plugins.trac.wordpress.org/browser/usc-e-shop/trunk/includes/order_print.php#L16
- https://plugins.trac.wordpress.org/browser/usc-e-shop/trunk/pdf/tcpdf/tcpdf.php#L7794
- https://plugins.trac.wordpress.org/changeset?reponame=&new=3673346%40usc-e-shop%2Ftags%2F2.12.2&old=3651925%40usc-e-shop%2Ftags%2F2.12.1
- https://plugins.trac.wordpress.org/changeset/3673344/usc-e-shop/trunk/classes/orderData.class.php
- https://plugins.trac.wordpress.org/changeset?old_path=%2Fusc-e-shop/tags/2.12.1&new_path=%2Fusc-e-shop/tags/2.12.2
More uscnanbu vulnerabilities
- TI-2023-05484 Welcart e-Commerce < 2.9.5 - Subscriber+ Arbitrary File Upload CVSS 3.1HIGH 8.8
- TI-2022-03880 Welcart e-Commerce < 2.8.6 - Subscriber+ PHAR Deserialisation CVSS 3.1HIGH 8.8
- TI-2022-03786 Welcart e-Commerce < 2.8.5 - Unauthenticated Arbitrary File Access CVSS 3.1HIGH 7.5
- TI-2026-84126 Cross-site scripting in Welcart e-Commerce Plugin payment error page CVSS 4.0MEDIUM 5.3
- TI-2022-03879 Welcart e-Commerce < 2.8.5 - Subscriber+ Arbitrary File Access CVSS 3.1MEDIUM 6.5
- TI-2022-03618 Welcart e-Commerce < 2.8.4 - Subscriber+ Arbitrary Shipping Method Creation/Update/Deletion CVSS 3.1MEDIUM 6.5
Sources
- CVE-2026-19887 · CVE Program
- CVE-2026-19887 · NVD
- FIRST EPSS
- GHSA-fq25-6gpx-5vxf · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences