CVE-2026-6858 is a stored XSS vulnerability (CWE-79) in the Transbank Webpay WordPress plugin prior to version 1.14.0. The vulnerability arises because the plugin does not properly sanitize and escape log data before displaying it in the administrator interface. This allows unauthenticated attackers to inject malicious scripts into logs, which execute when viewed by an administrator, potentially leading to cross-site scripting attacks with impacts on confidentiality, integrity, and availability.

Successful exploitation can lead to execution of arbitrary scripts in the context of an administrator user, potentially allowing theft of sensitive information, session hijacking, or other malicious actions affecting confidentiality, integrity, and availability of the affected system. The CVSS 3.1 base score is 7.1 (High), reflecting network attack vector, no privileges required, user interaction required, and scope change with low impact on confidentiality, integrity, and availability.

No official patch or remediation level is currently confirmed. Users should upgrade to version 1.14.0 or later once available, as the vulnerability affects versions before 1.14.0. Until a fix is released, restrict access to the plugin's logs to trusted users only and monitor for suspicious activity. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.