CVE-2026-56843
CriticalCVSS 9.9Exploitation Probability (EPSS)
Low risk26th percentile - higher than 26% of all known CVEs
Summary
A vulnerability in WebPros Plesk before version 18.0.78.4 allows a low-privileged authenticated customer to look up domains they do not own. This is due to incorrect authorization in the XML-RPC API, where ownership is enforced only for certain lookup filters and schema validation is bypassed for legacy protocol versions.
Risk Assessment
The risk involves disclosure of other tenants' FTP credentials stored in cleartext, which can be leveraged to execute code as another tenant's system user, leading to cross-tenant isolation breach.
Recommendation
It is recommended to immediately upgrade WebPros Plesk to version 18.0.78.4 or later, which includes a fix for this vulnerability.
Original NVD description (English source)
Incorrect authorization in the XML-RPC API of WebPros Plesk before 18.0.78.4 allows a low-privileged authenticated customer to look up domains they do not own, because ownership is enforced only for certain lookup filters and schema validation is bypassed for legacy protocol versions. This results in cross-tenant disclosure of other tenants' FTP credentials stored in cleartext, which can be leveraged to execute code as another tenant's system user.