CVE-2026-56843: WebPros Plesk

Critical severity, CVSS 9.9. EPSS: 0.7% chance of exploitation in the next 30 days.

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.

Affected products

• WebPros Plesk: from 10.4, before 18.0.78.4 (fixed in 18.0.78.4)

Published 2026-07-08. Last modified 2026-07-10.