CVE-2026-40551

Use of Client-Side Authentication in multiple BinSoft products

Published Apr 28, 2026 CVSS 4.0 · 8.4 High EPSS < 1% KEV · Not listed
Description
Multiple BinSoft products perform client-side authentication. An attacker with access to any application instance connected to the backend server can bypass the login verification process by manipulating the application binary and authenticate as an arbitrary user.

The described issue affects all published versions. The vendor stated that this issue is a direct result of the architecture model in which the software is distributed, and that it will be mitigated with a corrected installation manual.

Analysis

AI-generated

Technical impact

Multiple BinSoft products implement client‑side authentication, meaning the application validates login credentials locally rather than on the backend. An attacker who gains the ability to modify any instance’s binary can alter this logic and authenticate as any user without providing valid credentials. This flaw allows an attacker to obtain arbitrary user access, potentially exposing confidential data and enabling lateral movement. The weakness is identified as CWE‑603. The vendor attributes the problem to its distribution architecture model and plans to correct it with an updated installation manual.

Affected Systems

The vulnerability impacts all current BinSoft product releases, including mpCRM, mpFaktura, mpFirma, mpFirma ERP, mpGabinet, mpPOS, mpSekretariat, and mpWarsztat. Every published version contains client‑side authentication and is susceptible if the application binary can be tampered with; no version has been exempted, and the vendor has not yet released an update that removes the flaw.

Risk and Exploitability

The vulnerability carries a CVSS score of 8.4, indicating high severity. An EPSS score of 0.00192 (≈0.2 %) indicates a very low but nonzero likelihood of exploitation, and the lack of a KEV listing suggests no known large‑scale exploitation at this time. The likely attack vector involves an attacker with access to any instance of the affected BinSoft products that connects to the backend server; we infer that such access could be obtained either remotely through a public interface or locally by compromising a user’s machine. Once the binary is tampered with, the attacker can authenticate as an arbitrary user, leading to unauthorized system access.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Upgrade BinSoft products to the latest available releases, ensuring client‑side authentication (CWE‑603) is disabled and server‑side verification is enforced.
  • Disable any remaining client‑side authentication (CWE‑603) and force server‑side verification.
  • Restrict file permissions and enforce integrity checks (CWE‑603) on the application binary to prevent unauthorized tampering.

Generated by OpenCVE AI on October 2, 2026 at 00:25 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description mpGabinet performs client-side authentication. An attacker with access to any application instance connected to the backend server can bypass the login verification process by manipulating the application binary and authenticate as an arbitrary user. This issue affects mpGabinet version 23.12.19 and below. Multiple BinSoft products perform client-side authentication. An attacker with access to any application instance connected to the backend server can bypass the login verification process by manipulating the application binary and authenticate as an arbitrary user. The described issue affects all published versions. The vendor stated that this issue is a direct result of the architecture model in which the software is distributed, and that it will be mitigated with a corrected installation manual.
Title Use of Client-Side Authentication in mpGabinet Use of Client-Side Authentication in multiple BinSoft products
References
Type Values Removed Values Added
First Time appeared Binsoft
Binsoft mpgabinet
Vendors & Products Binsoft
Binsoft mpgabinet
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description mpGabinet performs client-side authentication. An attacker with access to any application instance connected to the backend server can bypass the login verification process by manipulating the application binary and authenticate as an arbitrary user. This issue affects mpGabinet version 23.12.19 and below.
Title Use of Client-Side Authentication in mpGabinet
Weaknesses CWE-603
References
Metrics cvssV4_0

{'score': 8.4, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N'}

Weaknesses
  • CWE-603

    Use of Client-Side Authentication

Sources

Status
PUBLISHED
Assigner
CERT-PL
Published
Updated
Sep 30, 2026, 11:18 AM
Reserved
Apr 14, 2026, 9:44 AM
Status
Deferred
Published
Apr 28, 2026, 2:16 PM
Modified
Oct 26, 2026, 9:10 PM