Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-76459

CVE-2026-76459CRITICAL

Cisco NX-OS Software Security Hardening Release: October 2026 - Out-of-bounds Write Vulnerabilities

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  H  H    9.8   .0031   22.0     —

AFFECTED
  Product                                   Versions    Fixed
  Cisco NX-OS Software                      8.2(5) –    —
  Cisco NX-OS System Software in ACI Mode   15.2(1g) –  —
  Cisco Unified Computing System (Managed)  4.0(1a) –   —

TIMELINE
  Aug 19  Reserved by cisco
  Oct 7   Published (CNA: cisco)
  Oct 9   RESCORED — CVE-2026-76459 (Cisco NX-OS Software). CVSS 8.8 → 9.8 (NVD).

CWE-787 · CNA: cisco · CVSS v3.1 · 1 reference · NVD status: Awaiting Analysis

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-2026-76459 are related to out-of-bounds write issues that are grouped under the Common Weakness Enumeration (CWE) CWE-787.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
August 19, 2026	Reserved	Reserved by cisco
October 7, 2026	Published	Published (CNA: cisco)
October 9, 2026	RESCORED	RESCORED — CVE-2026-76459 (Cisco NX-OS Software). CVSS 8.8 → 9.8 (NVD).

Affected

Affected products and packages — 3 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
Cisco	Cisco NX-OS Software	—	8.2(5)	—
Cisco	Cisco NX-OS System Software in ACI Mode	—	15.2(1g)	—
Cisco	Cisco Unified Computing System (Managed)	—	4.0(1a)	—

Weaknesses

CWE-787

References (1)

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

Authoritative record: CVE-2026-76459 at cve.org

Vendors: cisco

Weaknesses: CWE-787

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-76459 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.