PatchTheCVECVE-2026-56843: Incorrect authorization in the XML-RPC API of WebPros Plesk before 18.0.78.4 allows a low-privileged authentic
CVE-2026-56843 is a critical-severity flaw (CVSS 9.9) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 use
Why this priority
- Critical severity
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.9 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 0.7% (top 49%) |
| CISA exploited list | No |
| Weakness | CWE-522 |
| Published | 2026-07-08 |
| Last modified | 2026-10-25 |
Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-56843?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-56843 being exploited?
CVE-2026-56843 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-56843 affect?
CVE-2026-56843 affects affected software. Severity is critical (CVSS 9.9). 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 validat
How urgent is CVE-2026-56843?
Priority 47/100. Critical severity