Paper/Archive/CVE-2026-56843

CVE-2026-56843

Webpros Plesk — Incorrect authorization in the XML-RPC API of WebPros Plesk before 18.0.78.4 allows a low-privileged authenticated customer to look up do…

EPSS 0.7%CVSS 9.9

critical.is priorityof 100

CVSS 9.9 (CNA)9.9 / 10 × 3029.7 Not in CISA KEV+300.0 EPSS percentile 51.4.514 × 2010.3 No public exploit+100.0 SSVC exploitation: none+100.0

Description · from the CVE record

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

ProductAffectedFixed inSource

Plesk10.4 – < 18.0.78.418.0.78.4CNA

Scores by source

hackerone (CNA)9.9CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refsupport.plesk.com/hc/en-us/articles/41178305151255-Vulnerability-in-Plesk-XML-API-Cleartext-FTP-Password-Exposure