Security Resilience

CVE-2023-3634

Published
16 April 2026
Modified
17 April 2026
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0064 50th percentile
Risk Priority 65 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-2023-3634 is a high-severity Inclusion of Undocumented Features or Chicken Bits (CWE-1242) vulnerability in Certvde (inferred from references). Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Security Account Manager (T1003.002); ranked at the 50th 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 CM-7 (Least Functionality) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2023-3634 is a vulnerability in products of the MSE6 product-family by Festo. It stems from the exposure of functions in an undocumented test mode, which a remote authenticated low-privileged attacker could abuse. This issue, published on 2026-04-16, carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and is classified under CWE-1242.

The attack scenario involves a remote attacker who has obtained low-privilege authentication to the affected product. By leveraging the undocumented test mode functions, the attacker can achieve a complete loss of confidentiality, integrity, and availability, enabling full compromise of the targeted system.

Advisories detailing mitigations and patches are available from CERT VDE at https://certvde.com/de/advisories/VDE-2023-020/ and Festo's CSAF document at https://festo.csaf-tp.certvde.com/.well-known/csaf/white/2023/fsa-202304.json.

EU & UK References

Vulnerability Data

In products of the MSE6 product-family by Festo a remote authenticated, low privileged attacker could use functions of undocumented test mode which could lead to a complete loss of confidentiality, integrity and availability.

CWE(s)
CWE-1242

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
attack.mitre.org →
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
attack.mitre.org →
T1010 Application Window Discovery Discovery
Adversaries may attempt to get a listing of open application windows.
attack.mitre.org →
T1016 System Network Configuration Discovery Discovery
Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.
attack.mitre.org →
T1016.001 Internet Connection Discovery Discovery
Adversaries may check for Internet connectivity on compromised systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-12176Shared CWE-1242
CVE-2025-41754Shared CWE-1242
CVE-2024-7011Shared CWE-1242
CVE-2024-52564Shared CWE-1242
CVE-2025-52548Shared CWE-1242
CVE-2025-22450Shared CWE-1242
CVE-2024-54457Shared CWE-1242
CVE-2026-24714Shared CWE-1242
CVE-2024-2103Shared CWE-1242
CVE-2026-82928Shared CWE-1242

Affected Assets

Certvde
—
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)
  • V6.3.4

Mitigating Controls (NIST 800-53 r5) AI

CM-7 Least Functionality partial match

Least-functionality configuration can disable or remove non-essential capabilities once discovered, limiting the blast radius of any undocumented chicken bits that remain.

SA-15 Development Process, Standards, and Tools partial match

Documented development standards and processes directly require that all device features be specified and recorded, preventing hidden chicken bits from being introduced.

SA-3 System Development Life Cycle partial match

An SDLC that incorporates security requires all features to be captured in requirements and design artifacts, stopping undocumented capabilities from being added.

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles applied during design explicitly call for complete, documented functionality and the avoidance of hidden or undeclared mechanisms.

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.

ID.RA-09 partial match
blocks

Pre-acquisition integrity/authenticity assessment can discover undocumented features before deployment.

PR.PS-06 partial match
blocks

Secure SDLC practices directly reduce the chance of embedding chicken bits or hidden functionality.

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.8.25 Secure development life cycle partial match
blocks

Secure development life cycle requires documented design and review, reducing hidden or undocumented features.

A.8.26 Application security requirements partial match
removes
A.8.27 Secure system architecture and engineering principles partial match
blocks

A.8.27 mandates security-by-design, defence-in-depth, least privilege, assume-breach, distrust-external-input and hardening plus explicit review against known attack patterns; these reach some but not most chicken-bit/undocumented-feature cases (e.g. they can force documented disablement or removal of many backdoors), yet leave a bounded remainder where the undocumented feature is unknown to the designers or introduced post-review.

A.8.28 Secure coding partial match
prevents

Secure coding standards and peer review detect and prohibit undocumented or debug features.

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

Security testing in development and acceptance can uncover undocumented functionality before release.

A.8.32 Change management partial match
blocks

A.8.32 governs a formal, documented process for planning/assessing/authorizing/testing/implementing changes; it does not reach or block the presence of undocumented chicken bits or features that enable unauthorized entry

References