CVE-2026-0856Known exploitation

Admin-panel access via missing server-side authorization

Published May 20, 2026 · Updated May 20, 2026

Improper access control in Mesalvo Meona Client Launcher and Server components allows local users to access the admin panel. The .NET client enforces authorization on the client side, while the HTTP backend accepts normal-user credentials for administrative functions without verifying their permissions. A normal application account is required; successful exploitation exposes all data and functions in the administrative portal to that account.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Mesalvo Meona Client Launcher and Server components allows local users to access the admin panel. The .NET client enforces authorization on the client side, while the HTTP backend accepts normal-user credentials for administrative functions without verifying their permissions. A normal application account is required; successful exploitation exposes all data and functions in the administrative portal to that account.

The record

CVE
CVE-2026-0856
Published
May 20, 2026
Updated
May 20, 2026
Vendor
Mesalvo
Product
Meona Client Launcher Component
Classifications
CWE-284, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 20, 2026CVE publishedPublication date reported by the CVE source.
  2. May 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=19.06.2020 15:11:49

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Mesalvo · Meona Client Launcher Componentversion=0 <=19.06.2020 15:11:49
Mesalvo · Meona Server Componentversion=0 <=2025.04 5+323020

Published CVSS scores

7.8ENISACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Reported exploitation

Technologies

Your stack

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Your stack

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