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PatchSiren cyber security CVE debrief

CVE-2026-76457 Cisco CVE debrief

Cisco has addressed multiple out-of-bounds read vulnerabilities in their NX-OS Software Security Hardening Release for October 2026. The vulnerabilities, tracked by CVE-2026-76457, are related to out-of-bounds read issues grouped under CWE-125. This security hardening release is part of Cisco's ongoing commitment to proactive security and product quality. The vulnerabilities could potentially allow an attacker to read sensitive data. Cisco has provided patches and updates to address these vulnerabilities, and defenders should prioritize verifying affected versions, assessing exposure, and applying patches or updates.

Vendor
Cisco
Product
Cisco NX-OS Software
CVSS
HIGH 8.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-07
Original CVE updated
2026-10-07
Advisory published
2026-10-07
Advisory updated
2026-10-07

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 prioritize patching or mitigation.

Why it matters

CVE-2026-76457 is a high-severity vulnerability in Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed). Defenders should prioritize verifying affected versions, assessing exposure, and applying patches or updates to address the vulnerabilities.

  • Verify affected software versions to determine exposure.
  • Assess network configuration to determine potential attack vectors.
  • Apply patches or updates to address the vulnerabilities.
  • Monitor system logs for potential exploitation attempts.

Technical summary

CVE-2026-76457 is a high-severity vulnerability in Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed). The vulnerability is caused by out-of-bounds read issues, which could allow an attacker to read sensitive data. This vulnerability is grouped under CWE-125 and has a high CVSS score of 8.6. The vulnerability affects multiple versions of Cisco NX-OS Software, and defenders should prioritize verifying affected versions and assessing exposure. Cisco has provided patches and updates to address these vulnerabilities.

Defensive priority

Defenders should prioritize verifying affected versions and assessing exposure, as the vulnerability has a high CVSS score of 8.6.

Recommended defensive actions

  • Verify affected versions of Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed) in your environment.
  • Assess exposure based on your network configuration and software versions.
  • Apply patches or updates provided by Cisco to address the vulnerabilities.
  • Monitor system logs for potential exploitation 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 source corpus provides details on affected versions of Cisco NX-OS Software, Cisco NX-OS System Software in ACI Mode, and Cisco Unified Computing System (Managed). However, specific details on exploitation or impact are limited.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-76457 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-76457

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-76457 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-76457

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental 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.