How severe is CVE-2026-56843?

CVE-2026-56843 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-56843 being actively exploited?

It is not currently listed in CISA's Known Exploited Vulnerabilities catalog, and no EPSS exploit-prediction score is available yet.

How do I fix CVE-2026-56843?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-56843 published?

CVE-2026-56843 was published on 2026-07-08.

CVE-2026-56843

CVE-2026-56843 is a critical-severity vulnerability with a CVSS 3.x base score of 9.9. The underlying weakness is classified as CWE-522.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-522
Published: 2026-07-08
Last modified: 2026-07-08

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.

Frequently asked questions

What is CVE-2026-56843?: 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.
How severe is CVE-2026-56843?: CVE-2026-56843 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-56843 being actively exploited?: It is not currently listed in CISA's Known Exploited Vulnerabilities catalog, and no EPSS exploit-prediction score is available yet.
How do I fix CVE-2026-56843?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-56843 published?: CVE-2026-56843 was published on 2026-07-08.

References

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

Other CWE-522 (Insufficiently Protected Credentials) vulnerabilities

CVE-2026-7312 — Critical (CVSS 10.0): CWE‑522: Insufficiently Protected Credentials in web services in Progress Sitefinity version from 14.0.7700 to…
CVE-2026-29128 — Critical (CVSS 10.0): IDC SFX2100 Satellite Receiver firmware ships with multiple daemon configuration files for routing components (e.g.,…
CVE-2025-54863 — Critical (CVSS 10.0): Radiometrics VizAir is vulnerable to exposure of the system's REST API key through a publicly accessible configuration…
CVE-2024-12799 — Critical (CVSS 10.0): Insufficiently Protected Credentials vulnerability in OpenText Identity Manager Advanced Edition on Windows, Linux, 64…
CVE-2024-51545 — Critical (CVSS 10.0): Username Enumeration vulnerabilities allow access to application level username add, delete, modify and list…
CVE-2023-1778 — Critical (CVSS 10.0): This vulnerability exists in GajShield Data Security Firewall firmware versions prior to v4.28 (except v4.21) due to…

Browse all CWE-522 (Insufficiently Protected Credentials) vulnerabilities →