EUVD-2026-94458
GHSA-w55m-537w-hc8q
Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Retained vendor AV:N/AC:L/PR:N given sparse hardening-bundle detail; S:C and A:H with C:N/I:N reflect a cross-component denial of service with no data impact.
Primary rating from Vendor (cisco).
CVSS VectorVendor: cisco
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
Unauthenticated, network-reachable input-validation flaws in Cisco NX-OS Software command processing can disrupt affected devices, and the same hardening advisory covers Cisco NX-OS System Software running in ACI mode as well as the NX-OS component of Cisco Unified Computing System (managed). Cisco scores it 8.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H), so the assessed impact is availability-only with a scope change and no confidentiality or integrity effect. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Per the Cisco CVSS vector (AV:N/AC:L/PR:N/UI:N), no authentication or user interaction is required and the flaw is network-reachable against affected NX-OS devices; exploitation depends on the vulnerable NX-OS command-input processing being reachable from the attacker. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a Cisco-reported, internally-discovered vulnerability in Cisco NX-OS Software (including ACI mode and UCS managed variants), disclosed as part of a bundled hardening advisory rather than from external exploitation. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Cisco addressed this set of internally found issues through a software hardening release, and the fix is documented in Cisco's advisory at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-nxosw1-cWzSbtR; the supplied data does not identify a specific fixed version string, so remediation status is best described as patch available per vendor advisory, and administrators must map their exact NX-OS, ACI-mode, and UCS-managed release trains against that advisory to select the correct upgraded image before scheduling a maintenance window. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, confirm whether any Cisco NX-OS devices in your estate are network-exposed on management or data-plane interfaces, inventory all Cisco NX-OS System Software running in ACI mode and the NX-OS component of Cisco Unified Computing System (managed), and open a tracking ticket against CVE-2026-76456 noting CVSS 8.6 and that no vendor-released patch has been identified at time of analysis; simultaneously pull the Cisco security advisory and hardening guidance referenced for this CVE to confirm affected platform and release coverage. …
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External POC / Exploit Code
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