VDB-376743 · CVE-2026-56843 · GCVE-0-2026-56843

WebPros Plesk up to 18.0.78 XML-RPC API improper authorization

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.0	$0-$5k	0.58

Summaryinfo

A vulnerability has been found in WebPros Plesk and classified as critical. This issue affects some unknown processing of the component XML-RPC API. Performing a manipulation results in improper authorization. This vulnerability was named CVE-2026-56843. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, was found in WebPros Plesk. This affects an unknown part of the component XML-RPC API. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at support.plesk.com. This vulnerability is uniquely identified as CVE-2026-56843 since 06/23/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1548.002 according to MITRE ATT&CK.

Upgrading to version 18.0.78.4 eliminates this vulnerability.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Hosting Control Software

Vendor

WebPros

Name

Plesk

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authorization
CWE: CWE-285 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: Plesk 18.0.78.4

Timelineinfo

06/23/2026 CVE reserved
07/08/2026 +15 days Advisory disclosed
07/08/2026 +0 days VulDB entry created
07/08/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: support.plesk.com
Status: Confirmed

CVE: CVE-2026-56843 (🔒)
GCVE (CVE): GCVE-0-2026-56843
GCVE (VulDB): GCVE-100-376743

Entryinfo

Created: 07/08/2026 03:02
Changes: 07/08/2026 03:02 (54)
Complete: 🔍
Cache ID: 216::103