Vulnerability · Published Jul 8, 2026 · Assigned by hackerone
CVE-2026-56843
Critical 9.9
In plain English
A critical-severity security flaw in Plesk from Webpros. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).
Official description
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 (as reported)
Weakness: CWE-522 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H