CVE-2026-76456 - Vulnerability Details

- Cisco NX-OS Software Security Hardening Release: October 2026 - Improper Input Validation Vulnerabilities

Description

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco NX-OS engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-76456 are related to improper input validation of special elements used in a command issue that are grouped under the Common Weakness Enumeration (CWE) CWE-20.

Published: 2026-10-07

Score: 8.6 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

The vulnerability is an improper input validation flaw affecting special elements used in command issues, which can allow an attacker to embed additional commands and consequently execute arbitrary code on the device. The injected commands would run with the privileges of the user issuing them, potentially compromising device control and all hosted services.

Affected Systems

Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed). Any deployment running these products prior to the October 2026 hardening release is potentially vulnerable, as the advisory does not list specific firmware or software versions.

Risk and Exploitability

The CVSS score of 8.6 classifies this flaw as high severity, but the EPSS score is not available, so exploitation probability cannot be quantified. The vulnerability is not listed in the CISA KEV catalog. Based on the description, it is inferred that the likely attack vector is a privileged management interface or device console where an attacker can send a crafted command that bypasses normal input checks. The weakness is identified as CWE-20 (Improper Input Validation).

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco NX-OS Software

unknown

Version	Status	Constraints
`8.2(5)`	affected	—
`7.3(5)D1(1)`	affected	—
`8.4(2)`	affected	—
`8.4(3)`	affected	—
`9.2(3)`	affected	—
`8.2(1)`	affected	—
`7.3(1)D1(1)`	affected	—
`9.2(2v)`	affected	—
`7.3(0)D1(1)`	affected	—
`7.3(4)D1(1)`	affected	—
`9.2(1)`	affected	—
`9.2(2t)`	affected	—
`9.2(3y)`	affected	—
`9.3(2)`	affected	—
`7.3(1)DY(1)`	affected	—
`8.1(1)`	affected	—
`8.2(2)`	affected	—
`8.3(2)`	affected	—
`7.3(2)D1(3a)`	affected	—
`9.2(4)`	affected	—
`8.1(2)`	affected	—
`7.3(3)D1(1)`	affected	—
`8.2(3)`	affected	—
`8.3(1)`	affected	—
`8.4(1)`	affected	—
`8.1(1b)`	affected	—
`7.3(0)DX(1)`	affected	—
`7.3(2)D1(1)`	affected	—
`9.3(1)`	affected	—
`7.3(2)D1(2)`	affected	—
`8.2(4)`	affected	—
`7.3(0)DY(1)`	affected	—
`9.3(1z)`	affected	—
`9.2(2)`	affected	—
`8.1(2a)`	affected	—
`7.3(2)D1(3)`	affected	—
`8.1(1a)`	affected	—
`8.4(1a)`	affected	—
`9.3(3)`	affected	—
`7.3(2)D1(1d)`	affected	—
`9.3(4)`	affected	—
`7.3(6)D1(1)`	affected	—
`8.2(6)`	affected	—
`9.3(5)`	affected	—
`8.4(2a)`	affected	—
`8.4(2b)`	affected	—
`8.5(1)`	affected	—
`9.3(6)`	affected	—
`8.4(4)`	affected	—
`7.3(7)D1(1)`	affected	—
`8.4(2c)`	affected	—
`9.3(5w)`	affected	—
`8.2(7)`	affected	—
`9.3(7)`	affected	—
`9.3(7k)`	affected	—
`7.3(8)D1(1)`	affected	—
`9.3(7a)`	affected	—
`8.2(7a)`	affected	—
`9.3(8)`	affected	—
`8.4(4a)`	affected	—
`8.4(2d)`	affected	—
`8.4(5)`	affected	—
`8.2(8)`	affected	—
`9.3(9)`	affected	—
`7.3(9)D1(1)`	affected	—
`8.4(6)`	affected	—
`8.4(2e)`	affected	—
`9.3(10)`	affected	—
`9.2(1a)`	affected	—
`8.2(9)`	affected	—
`10.3(1)`	affected	—
`8.4(7)`	affected	—
`10.3(2)`	affected	—
`8.4(6a)`	affected	—
`9.3(11)`	affected	—
`10.3(3)`	affected	—
`9.4(1)`	affected	—
`9.3(2a)`	affected	—
`8.4(2f)`	affected	—
`8.2(10)`	affected	—
`9.3(12)`	affected	—
`10.4(1)`	affected	—
`8.4(8)`	affected	—
`10.3(99w)`	affected	—
`10.3(3w)`	affected	—
`10.3(99x)`	affected	—
`10.3(3o)`	affected	—
`8.4(9)`	affected	—
`10.3(4)`	affected	—
`10.3(3p)`	affected	—
`10.3(4a)`	affected	—
`9.4(1a)`	affected	—
`10.4(2)`	affected	—
`10.3(3q)`	affected	—
`9.3(13)`	affected	—
`8.2(11)`	affected	—
`9.4(2)`	affected	—
`10.3(5)`	affected	—
`10.4(3)`	affected	—
`10.3(3x)`	affected	—
`10.3(4g)`	affected	—
`10.5(1)`	affected	—
`8.4(10)`	affected	—
`9.4(2a)`	affected	—
`10.3(3r)`	affected	—
`10.3(6)`	affected	—
`9.3(14)`	affected	—
`10.4(4)`	affected	—
`10.3(4h)`	affected	—
`10.5(2)`	affected	—
`10.5(1j)`	affected	—
`8.4(11)`	affected	—
`9.4(3)`	affected	—
`10.3(7)`	affected	—
`10.4(5)`	affected	—
`10.5(3)`	affected	—
`9.3(15)`	affected	—
`9.4(3a)`	affected	—
`10.4(4g)`	affected	—
`10.5(4)`	affected	—
`9.4(3b)`	affected	—
`8.4(12)`	affected	—
`10.6(1)`	affected	—
`10.5(3t)`	affected	—
`10.3(8)`	affected	—
`10.4(6)`	affected	—
`10.5(3s)`	affected	—
`10.5(3e)`	affected	—
`9.4(4)`	affected	—
`10.5(3o)`	affected	—
`9.3(16)`	affected	—
`10.6(1s)`	affected	—
`10.6(2)`	affected	—
`10.5(3p)`	affected	—
`9.4(5)`	affected	—
`10.3(9)`	affected	—
`10.6(2s)`	affected	—
`8.4(13)`	affected	—
`10.6(3)`	affected	—
`10.4(7)`	affected	—
`10.5(5)`	affected	—
`9.3(17)`	affected	—
`10.6(2n)`	affected	—
`10.6(3q)`	affected	—
`10.6(3o)`	affected	—
`10.6(3s)`	affected	—
`7.3(18)N1(1)`	affected	—

Cisco

Cisco NX-OS System Software in ACI Mode

unknown

Version	Status	Constraints
`15.2(1g)`	affected	—
`15.2(2e)`	affected	—
`15.2(2f)`	affected	—
`15.2(2g)`	affected	—
`15.2(2h)`	affected	—
`15.2(3f)`	affected	—
`15.2(3e)`	affected	—
`15.2(3g)`	affected	—
`15.2(4d)`	affected	—
`15.2(4e)`	affected	—
`15.2(5c)`	affected	—
`15.2(5d)`	affected	—
`16.0(1g)`	affected	—
`15.2(5e)`	affected	—
`15.2(4f)`	affected	—
`15.2(6e)`	affected	—
`15.2(6h)`	affected	—
`16.0(1j)`	affected	—
`15.2(6g)`	affected	—
`15.2(7f)`	affected	—
`15.2(7g)`	affected	—
`16.0(2h)`	affected	—
`15.2(8d)`	affected	—
`16.0(2j)`	affected	—
`15.2(8e)`	affected	—
`16.0(3d)`	affected	—
`16.0(3e)`	affected	—
`15.2(8f)`	affected	—
`15.2(8g)`	affected	—
`15.3(1d)`	affected	—
`15.2(8h)`	affected	—
`16.0(4c)`	affected	—
`15.3(2a)`	affected	—
`15.2(8i)`	affected	—
`16.0(5h)`	affected	—
`15.3(2b)`	affected	—
`16.0(3g)`	affected	—
`16.0(5j)`	affected	—
`15.3(2c)`	affected	—
`16.0(6c)`	affected	—
`15.3(2d)`	affected	—
`16.1(1f)`	affected	—
`16.0(7e)`	affected	—
`16.0(8e)`	affected	—
`15.3(2e)`	affected	—
`16.0(8f)`	affected	—
`16.1(2f)`	affected	—
`16.1(2g)`	affected	—
`15.3(2f)`	affected	—
`16.0(9c)`	affected	—
`16.1(3f)`	affected	—
`16.0(9d)`	affected	—
`16.0(6h)`	affected	—
`16.0(8h)`	affected	—
`16.1(3g)`	affected	—
`16.0(9e)`	affected	—
`16.1(4h)`	affected	—
`16.1(5e)`	affected	—
`16.2(1g)`	affected	—
`16.0(9f)`	affected	—
`16.2(2e)`	affected	—

Cisco

Cisco Unified Computing System (Managed)

unknown

Version	Status	Constraints
`4.0(1a)`	affected	—
`4.1(1a)`	affected	—
`4.1(1b)`	affected	—
`4.0(4h)`	affected	—
`4.1(1c)`	affected	—
`4.0(4e)`	affected	—
`4.0(4g)`	affected	—
`4.0(2e)`	affected	—
`4.0(4a)`	affected	—
`4.0(2d)`	affected	—
`4.0(1b)`	affected	—
`4.0(4f)`	affected	—
`4.0(4c)`	affected	—
`4.0(1c)`	affected	—
`4.0(4b)`	affected	—
`4.0(2b)`	affected	—
`4.0(4d)`	affected	—
`4.0(2a)`	affected	—
`4.0(1d)`	affected	—
`4.0(4i)`	affected	—
`4.1(1d)`	affected	—
`4.1(2a)`	affected	—
`4.1(1e)`	affected	—
`4.1(2b)`	affected	—
`4.0(4k)`	affected	—
`4.1(3a)`	affected	—
`4.1(3b)`	affected	—
`4.1(2c)`	affected	—
`4.0(4l)`	affected	—
`4.1(4a)`	affected	—
`4.1(3c)`	affected	—
`4.1(3d)`	affected	—
`4.2(1c)`	affected	—
`4.2(1d)`	affected	—
`4.0(4m)`	affected	—
`4.1(3e)`	affected	—
`4.2(1f)`	affected	—
`4.1(3f)`	affected	—
`4.2(1i)`	affected	—
`4.1(3h)`	affected	—
`4.2(1k)`	affected	—
`4.2(1l)`	affected	—
`4.0(4n)`	affected	—
`4.2(1m)`	affected	—
`4.1(3i)`	affected	—
`4.2(2a)`	affected	—
`4.2(1n)`	affected	—
`4.1(3j)`	affected	—
`4.2(2c)`	affected	—
`4.2(2d)`	affected	—
`4.2(3b)`	affected	—
`4.1(3k)`	affected	—
`4.0(4o)`	affected	—
`4.2(2e)`	affected	—
`4.2(3d)`	affected	—
`4.2(3e)`	affected	—
`4.2(3g)`	affected	—
`4.1(3l)`	affected	—
`4.3(2b)`	affected	—
`4.2(3h)`	affected	—
`4.2(3i)`	affected	—
`4.3(2c)`	affected	—
`4.1(3m)`	affected	—
`4.3(2e)`	affected	—
`4.3(3a)`	affected	—
`4.2(3j)`	affected	—
`4.3(3c)`	affected	—
`4.3(4a)`	affected	—
`4.2(3k)`	affected	—
`4.3(4b)`	affected	—
`4.3(4c)`	affected	—
`4.2(3l)`	affected	—
`4.3(4d)`	affected	—
`4.3(2f)`	affected	—
`4.2(3m)`	affected	—
`4.3(5a)`	affected	—
`4.3(4e)`	affected	—
`4.1(3n)`	affected	—
`4.3(4f)`	affected	—
`4.2(3n)`	affected	—
`4.3(5c)`	affected	—
`4.2(3o)`	affected	—
`4.3(5d)`	affected	—
`4.3(6a)`	affected	—
`4.3(6b)`	affected	—
`4.3(5e)`	affected	—
`4.3(6c)`	affected	—
`6.0(1b)`	affected	—
`4.2(3p)`	affected	—
`6.0(1c)`	affected	—
`4.3(6d)`	affected	—
`6.0(1d)`	affected	—
`6.0(1e)`	affected	—
`4.3(6e)`	affected	—
`6.0(1f)`	affected	—
`4.3(6f)`	affected	—
`6.0(2b)`	affected	—
`6.0(1h)`	affected	—
`4.2(3r)`	affected	—
`6.0(2c)`	affected	—
`4.3(6g)`	affected	—
`6.0(2d)`	affected	—
`4.3(6h)`	affected	—
`4.2(3s)`	affected	—
`4.3(6i)`	affected	—

No data.

Vendor Product Confidence Versions

Cisco

Cisco Nx-os System Software In Aci Mode

100%

Version	Status	Scheme	Platform
`[15.2(1g),16.2(2e)]`	affected	generic	—

Cisco

Nx-os Software

87%

Version	Status	Scheme	Platform
`[7.3(0)D1(1),10.6(3q)]`	affected	generic	—

Cisco

Unified Computing System Manager

89%

Version	Status	Scheme	Platform
`[4.0(1a),6.0(2d)]`	affected	generic	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Cisco NX-OS to the hardening release released in October 2026.
Implement strict input validation for command parsing so that special elements are sanitized before execution.
Restrict or disable legacy command interfaces that accept unvalidated input and limit privileged command issuance to authorized users only.

Generated by OpenCVE AI on October 7, 2026 at 18:42 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00278.

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-nxosw1-cWzSbtR

History

Sun, 11 Oct 2026 12:30:00 +0000

Type	Values Removed	Values Added
First Time appeared		Cisco Cisco cisco Nx-os System Software In Aci Mode Cisco nx-os Software Cisco unified Computing System Manager
Vendors & Products		Cisco Cisco cisco Nx-os System Software In Aci Mode Cisco nx-os Software Cisco unified Computing System Manager

Wed, 07 Oct 2026 19:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Wed, 07 Oct 2026 16:30:00 +0000

Type	Values Removed	Values Added
Description		As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco NX-OS engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-76456 are related to improper input validation of special elements used in a command issue that are grouped under the Common Weakness Enumeration (CWE) CWE-20.
Title		Cisco NX-OS Software Security Hardening Release: October 2026 - Improper Input Validation Vulnerabilities
Weaknesses		CWE-20
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-nxosw1-cWzSbtR
Metrics		cvssV3_1 `{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}`

Subscriptions

Cisco Cisco Nx-os System Software In Aci Mode Nx-os Software Unified Computing System Manager

MITRE

Status: PUBLISHED

Assigner: cisco

Published: 2026-10-07T16:15:11.980Z

Updated: 2026-10-07T18:05:35.961Z

Reserved: 2026-08-19T12:02:03.637Z

Link: CVE-2026-76456

Vulnrichment

Updated: 2026-10-07T18:02:42.590Z

NVD

Status : Awaiting Analysis

Published: 2026-10-07T17:16:57.770

Modified: 2026-10-08T20:08:45.857

Link: CVE-2026-76456

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-10-11T12:15:18Z

Weaknesses

CWE-20
Improper Input Validation

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Exploitation none

Automatable yes

Technical Impact partial

Subscriptions

JSON object

JSON object

JSON object

JSON object

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