Security Resilience

CVE-2023-20012

Auth Bypass in Cisco Ucs Central Software 4.2 – 4.2\(2d\)

Published
23 February 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 5.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.0029 21th percentile
Risk Priority 39 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-2023-20012 is a medium-severity Improper Authentication (CWE-287) vulnerability in Cisco Ucs Central Software. Its CVSS base score is 5.3 (Medium).

Operationally, ranked at the 21th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A vulnerability in the CLI console login authentication of Cisco Nexus 9300-FX3 Series Fabric Extender (FEX) when used in UCS Fabric Interconnect deployments could allow an unauthenticated attacker with physical access to bypass authentication. This vulnerability is due to the…

more

improper implementation of the password validation function. An attacker could exploit this vulnerability by logging in to the console port on an affected device. A successful exploit could allow the attacker to bypass authentication and execute a limited set of commands local to the FEX, which could cause a device reboot and denial of service (DoS) condition.

CWE(s)

Related Threats

CVEs Like This One

CVE-2026-20129Same vendor: Cisco
CVE-2025-20160Same vendor: Cisco
CVE-2023-20214Same vendor: Cisco
CVE-2026-20182Same vendor: Cisco
CVE-2023-20238Same vendor: Cisco
CVE-2023-20199Same vendor: Cisco
CVE-2026-20127Same vendor: Cisco
CVE-2019-1937Same vendor: Cisco
CVE-2023-20252Same vendor: Cisco
CVE-2024-20301Same vendor: Cisco

Affected Assets

cisco
nexus 93180yc-fx3s firmware
all versions
cisco
nexus 93180yc-fx3 firmware
all versions
cisco
ucs central software
4.2 — 4.2\(2d\) · 4.2 — 4.2\(2d\) · 4.2 — 4.2\(2d\)
cisco
ucs 6536 firmware
all versions
cisco
ucs 64108 firmware
all versions
cisco
ucs 6454 firmware
all versions

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-287

Detects unauthorized successful logons resulting from improper authentication implementations.

addresses: CWE-287

Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.

addresses: CWE-287

Security awareness training instructs users on secure authentication practices and avoiding credential compromise.

addresses: CWE-287

Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.

addresses: CWE-287

Non-repudiation requires strong authentication mechanisms to irrefutably attribute performed actions to specific individuals or processes.

addresses: CWE-287

Session content review can reveal authentication bypasses or failures in session establishment.

addresses: CWE-287

Review of authentication-related audit records can detect improper authentication mechanisms or bypasses.

addresses: CWE-287

Assessments check authentication mechanisms for correct implementation and effectiveness, reducing successful authentication bypass attempts.

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.

blocks

Mandating segregated approval and oversight for non-human identities reduces the chance that weak or orphaned credentials can be exploited for unauthorized authentication.

blocks

A.5.17 directly mandates generation of non-guessable unique secrets, secure transmission, immediate change of defaults/temporary creds, strong password enforcement, no-reuse, and compromise response, which stops most improper-authentication exploits at source; the bounded remainder is non-password authentication methods and sufficiency-of-proof cases (e.g. IA-2/IA-5 enhancements) left to other controls.

blocks

Security requirements specified early and verified through testing drive the consistent implementation of authentication mechanisms, decreasing the likelihood that authentication steps are omitted or incorrectly applied.

blocks

A.8.26 explicitly requires identifying and addressing authentication-related requirements (including level of trust in identity via 8.5 and 5.17) as part of application development or acquisition, which prevents a slice of CWE-287 but leaves the dominant sufficiency-of-proof aspects (IA-2/IA-5) and many implementation defects untouched.

blocks

A.8.27 mandates security-by-design principles (least privilege, default-deny, never-trust/always-verify, MFA, end-to-end encryption of requests, distrust-external-input, secure session control, and explicit authentication/authorization in every layer), which directly stops most improper-authentication flaws from being exploitable; the bounded remainder is insufficient-proof cases that live only in the strength or correctness of the credential itself (IA-5/IA-2 territory).

blocks

A.8.5 directly mandates appropriate-strength authentication techniques, MFA for critical systems, protected log-on procedures, brute-force resistance, no cleartext passwords/transmission, and session controls that stop exploitation of insufficient proof of identity; the bounded remainder is cases where the chosen technique itself is flawed or insufficiently implemented (e.g. weak biometrics without fallback).

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-287, a class-level weakness. Rules are authored against its narrower children: CWE-295, CWE-306.

References