Critical severity · published Oct 7, 2026
CVE-2026-76459
Cisco NX-OS Software Security Hardening Release: October 2026 - Out-of-bounds Write Vulnerabilities
9.8
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 23% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CN
Cisco NX-OS Software · Cisco
8.2(5); 7.3(5)D1(1); 8.4(2); 8.4(3); 9.2(3); 8.2(1); +34 more · source: vendor
CN
Cisco NX-OS System Software in ACI Mode · Cisco
15.2(1g); 15.2(2e); 15.2(2f); 15.2(2g); 15.2(2h); 15.2(3f); +34 more · source: vendor
CU
Cisco Unified Computing System (Managed) · Cisco
4.0(1a); 4.1(1d); 4.0(4f); 4.0(4c); 4.0(2b); 4.1(2a); +34 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-76459
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-76459
sec.cloudapps.cisco.com
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-nxosw1-cWzSbtR
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