CVE-2026-19887

HIGH
Published Sep 5, 2026 Modified Sep 8, 2026 CWE-502

Description

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.

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CVSS v3.1 Score

8.8
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0057
Probability of exploitation
0.46%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

References

Other References

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/classes/orderData.class.php#L41 https://plugins.trac.wordpress.org/browser/usc-e-shop/trunk/functions/function.php#L218 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/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/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 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://www.wordfence.com/threat-intel/vulnerabilities/id/716a7c3c-2e26-4da9-a299-7dcbaa7e4895?source=cve

Frequently Asked Questions

What is CVE-2026-19887? +
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. It has a CVSS v3.1 base score of 8.8 (HIGH).
How severe is CVE-2026-19887? +
CVE-2026-19887 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0057, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-19887? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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