Cyber Resilience

CVE-2026-40551

Published
28 April 2026
Modified
28 April 2026
CVSS Score v4 8.4
Click a component to see what it means
Raw vectorCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0013 3th percentile
Risk Priority 30 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-40551 is a high-severity Use of Client-Side Authentication (CWE-603) vulnerability in Cert (inferred from references). Its CVSS base score is 8.4 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and IA-2 (Identification and Authentication (Organizational Users)) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

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…

more

and below.

CWE(s)
CWE-603

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-8830Shared CWE-603
CVE-2026-66305Shared CWE-603
CVE-2025-30042Shared CWE-603
CVE-2025-12868Shared CWE-603
CVE-2025-62650Shared CWE-603
CVE-2026-1363Shared CWE-603
CVE-2024-45785Shared CWE-603
CVE-2024-39375Shared CWE-603
CVE-2025-62649Shared CWE-603
CVE-2025-61940Shared CWE-603

Affected Assets

Cert
—
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V10.4.10
  • V10.4.15
  • V10.4.16
  • V10.7.1

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match

Enforces access authorizations on the server, making client-side bypass ineffective.

IA-2 Identification and Authentication (Organizational Users) good match

Requires server-side identification and authentication of users before granting access.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 partial match
prevents

Server-enforced authentication directly prevents client-only checks from being bypassed.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.26 Application security requirements partial match
prevents

Defines application security requirements that include server-side authentication enforcement.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Promotes secure architecture principles that reject client-only authentication designs.

A.8.28 Secure coding partial match
prevents

Secure coding standards discourage reliance on client-side authentication logic.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing can detect missing server-side authentication checks.

A.8.3 Information access restriction partial match
mitigates

Enforces access restrictions that must be validated on the server, mitigating client-side bypass.

A.8.5 Secure authentication partial match
prevents

Requires server-side authentication mechanisms that directly prevent client-only checks.

References