CVE-2026-76455 Cisco CVE debrief

Who should care

Defenders responsible for Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed) deployments should assess exposure and apply remediation. This includes administrators and security teams managing these systems.

Why it matters

CVE-2026-76455 requires verification of exposure and application of Cisco's security hardening release to prevent potential unauthorized access. Defenders should prioritize remediation due to the critical severity of the vulnerabilities.

• Verify exposure in inventory and assess affected versions
• Apply Cisco's security hardening release for October 2026 to prevent potential unauthorized access
• Monitor for potential security incidents related to these vulnerabilities
• Prioritize remediation based on the critical severity of the vulnerabilities

Technical summary

CVE-2026-76455 addresses multiple improper access control issues in Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed). The vulnerabilities were discovered during an internal security review by Cisco. Affected products include Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed). Defenders should prioritize verifying exposure in their inventory, assessing affected versions, and applying vendor remediation to prevent potential unauthorized access.

Defensive priority

Defenders should prioritize verifying exposure in their inventory, assessing affected versions, and applying vendor remediation.

Recommended defensive actions

• Verify inventory for affected Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed) versions
• Assess exposure based on known affected versions
• Apply Cisco's security hardening release for October 2026
• Monitor for potential unauthorized access attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the vulnerabilities and affected versions. However, specific exploitation or impact data is not provided, requiring verification from official sources.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.