CVE-2026-76459

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

Published Oct 7, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed

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.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco NX-OS Software

unknown

Version	Status	Constraints
`8.2(5)`	affected	—
`7.3(5)D1(1)`	affected	—
`8.4(2)`	affected	—
`8.4(3)`	affected	—
`9.2(3)`	affected	—
`8.2(1)`	affected	—
`7.3(1)D1(1)`	affected	—
`9.2(2v)`	affected	—
`7.3(0)D1(1)`	affected	—
`7.3(4)D1(1)`	affected	—
`9.2(1)`	affected	—
`9.2(2t)`	affected	—
`9.2(3y)`	affected	—
`9.3(2)`	affected	—
`7.3(1)DY(1)`	affected	—
`8.1(1)`	affected	—
`8.2(2)`	affected	—
`8.3(2)`	affected	—
`7.3(2)D1(3a)`	affected	—
`9.2(4)`	affected	—
`8.1(2)`	affected	—
`7.3(3)D1(1)`	affected	—
`8.2(3)`	affected	—
`8.3(1)`	affected	—
`8.4(1)`	affected	—
`8.1(1b)`	affected	—
`7.3(0)DX(1)`	affected	—
`7.3(2)D1(1)`	affected	—
`9.3(1)`	affected	—
`7.3(2)D1(2)`	affected	—
`8.2(4)`	affected	—
`7.3(0)DY(1)`	affected	—
`9.3(1z)`	affected	—
`9.2(2)`	affected	—
`8.1(2a)`	affected	—
`7.3(2)D1(3)`	affected	—
`8.1(1a)`	affected	—
`8.4(1a)`	affected	—
`9.3(3)`	affected	—
`7.3(2)D1(1d)`	affected	—
`9.3(4)`	affected	—
`7.3(6)D1(1)`	affected	—
`8.2(6)`	affected	—
`9.3(5)`	affected	—
`8.4(2a)`	affected	—
`8.4(2b)`	affected	—
`8.5(1)`	affected	—
`9.3(6)`	affected	—
`8.4(4)`	affected	—
`7.3(7)D1(1)`	affected	—
`8.4(2c)`	affected	—
`9.3(5w)`	affected	—
`8.2(7)`	affected	—
`9.3(7)`	affected	—
`9.3(7k)`	affected	—
`7.3(8)D1(1)`	affected	—
`9.3(7a)`	affected	—
`8.2(7a)`	affected	—
`9.3(8)`	affected	—
`8.4(4a)`	affected	—
`8.4(2d)`	affected	—
`8.4(5)`	affected	—
`8.2(8)`	affected	—
`9.3(9)`	affected	—
`7.3(9)D1(1)`	affected	—
`8.4(6)`	affected	—
`8.4(2e)`	affected	—
`9.3(10)`	affected	—
`9.2(1a)`	affected	—
`8.2(9)`	affected	—
`10.3(1)`	affected	—
`8.4(7)`	affected	—
`10.3(2)`	affected	—
`8.4(6a)`	affected	—
`9.3(11)`	affected	—
`10.3(3)`	affected	—
`9.4(1)`	affected	—
`9.3(2a)`	affected	—
`8.4(2f)`	affected	—
`8.2(10)`	affected	—
`9.3(12)`	affected	—
`10.4(1)`	affected	—
`8.4(8)`	affected	—
`10.3(99w)`	affected	—
`10.3(3w)`	affected	—
`10.3(99x)`	affected	—
`10.3(3o)`	affected	—
`8.4(9)`	affected	—
`10.3(4)`	affected	—
`10.3(3p)`	affected	—
`10.3(4a)`	affected	—
`9.4(1a)`	affected	—
`10.4(2)`	affected	—
`10.3(3q)`	affected	—
`9.3(13)`	affected	—
`8.2(11)`	affected	—
`9.4(2)`	affected	—
`10.3(5)`	affected	—
`10.4(3)`	affected	—
`10.3(3x)`	affected	—
`10.3(4g)`	affected	—
`10.5(1)`	affected	—
`8.4(10)`	affected	—
`9.4(2a)`	affected	—
`10.3(3r)`	affected	—
`10.3(6)`	affected	—
`9.3(14)`	affected	—
`10.4(4)`	affected	—
`10.3(4h)`	affected	—
`10.5(2)`	affected	—
`10.5(1j)`	affected	—
`8.4(11)`	affected	—
`9.4(3)`	affected	—
`10.3(7)`	affected	—
`10.4(5)`	affected	—
`10.5(3)`	affected	—
`9.3(15)`	affected	—
`9.4(3a)`	affected	—
`10.4(4g)`	affected	—
`10.5(4)`	affected	—
`9.4(3b)`	affected	—
`8.4(12)`	affected	—
`10.6(1)`	affected	—
`10.5(3t)`	affected	—
`10.3(8)`	affected	—
`10.4(6)`	affected	—
`10.5(3s)`	affected	—
`10.5(3e)`	affected	—
`9.4(4)`	affected	—
`10.5(3o)`	affected	—
`9.3(16)`	affected	—
`10.6(1s)`	affected	—
`10.6(2)`	affected	—
`10.5(3p)`	affected	—
`9.4(5)`	affected	—
`10.3(9)`	affected	—
`10.6(2s)`	affected	—
`8.4(13)`	affected	—
`10.6(3)`	affected	—
`10.4(7)`	affected	—
`10.5(5)`	affected	—
`9.3(17)`	affected	—
`10.6(2n)`	affected	—
`10.6(3q)`	affected	—
`10.6(3o)`	affected	—
`10.6(3s)`	affected	—

Cisco

Cisco NX-OS System Software in ACI Mode

unknown

Version	Status	Constraints
`15.2(1g)`	affected	—
`15.2(2e)`	affected	—
`15.2(2f)`	affected	—
`15.2(2g)`	affected	—
`15.2(2h)`	affected	—
`15.2(3f)`	affected	—
`15.2(3e)`	affected	—
`15.2(3g)`	affected	—
`15.2(4d)`	affected	—
`15.2(4e)`	affected	—
`15.2(5c)`	affected	—
`15.2(5d)`	affected	—
`16.0(1g)`	affected	—
`15.2(5e)`	affected	—
`15.2(4f)`	affected	—
`15.2(6e)`	affected	—
`15.2(6h)`	affected	—
`16.0(1j)`	affected	—
`15.2(6g)`	affected	—
`15.2(7f)`	affected	—
`15.2(7g)`	affected	—
`16.0(2h)`	affected	—
`15.2(8d)`	affected	—
`16.0(2j)`	affected	—
`15.2(8e)`	affected	—
`16.0(3d)`	affected	—
`16.0(3e)`	affected	—
`15.2(8f)`	affected	—
`15.2(8g)`	affected	—
`15.3(1d)`	affected	—
`15.2(8h)`	affected	—
`16.0(4c)`	affected	—
`15.3(2a)`	affected	—
`15.2(8i)`	affected	—
`16.0(5h)`	affected	—
`15.3(2b)`	affected	—
`16.0(3g)`	affected	—
`16.0(5j)`	affected	—
`15.3(2c)`	affected	—
`16.0(6c)`	affected	—
`15.3(2d)`	affected	—
`16.1(1f)`	affected	—
`16.0(7e)`	affected	—
`16.0(8e)`	affected	—
`15.3(2e)`	affected	—
`16.0(8f)`	affected	—
`16.1(2f)`	affected	—
`16.1(2g)`	affected	—
`15.3(2f)`	affected	—
`16.0(9c)`	affected	—
`16.1(3f)`	affected	—
`16.0(9d)`	affected	—
`16.0(6h)`	affected	—
`16.0(8h)`	affected	—
`16.1(3g)`	affected	—
`16.0(9e)`	affected	—
`16.1(4h)`	affected	—
`16.1(5e)`	affected	—
`16.2(1g)`	affected	—
`16.0(9f)`	affected	—
`16.2(2e)`	affected	—

Cisco

Cisco Unified Computing System (Managed)

unknown

Version	Status	Constraints
`4.0(1a)`	affected	—
`4.1(1d)`	affected	—
`4.0(4f)`	affected	—
`4.0(4c)`	affected	—
`4.0(2b)`	affected	—
`4.1(2a)`	affected	—
`4.0(4a)`	affected	—
`4.0(4e)`	affected	—
`4.0(4h)`	affected	—
`4.0(2a)`	affected	—
`4.1(1c)`	affected	—
`4.0(1b)`	affected	—
`4.1(1e)`	affected	—
`4.0(4d)`	affected	—
`4.0(4b)`	affected	—
`4.0(2e)`	affected	—
`4.1(1a)`	affected	—
`4.0(4g)`	affected	—
`4.0(1d)`	affected	—
`4.0(1c)`	affected	—
`4.0(4i)`	affected	—
`4.0(2d)`	affected	—
`4.1(1b)`	affected	—
`4.1(2b)`	affected	—
`4.0(4k)`	affected	—
`4.1(3a)`	affected	—
`4.1(3b)`	affected	—
`4.1(2c)`	affected	—
`4.0(4l)`	affected	—
`4.1(4a)`	affected	—
`4.1(3c)`	affected	—
`4.1(3d)`	affected	—
`4.2(1c)`	affected	—
`4.2(1d)`	affected	—
`4.0(4m)`	affected	—
`4.1(3e)`	affected	—
`4.2(1f)`	affected	—
`4.1(3f)`	affected	—
`4.2(1i)`	affected	—
`4.1(3h)`	affected	—
`4.2(1k)`	affected	—
`4.2(1l)`	affected	—
`4.0(4n)`	affected	—
`4.2(1m)`	affected	—
`4.1(3i)`	affected	—
`4.2(2a)`	affected	—
`4.2(1n)`	affected	—
`4.1(3j)`	affected	—
`4.2(2c)`	affected	—
`4.2(2d)`	affected	—
`4.2(3b)`	affected	—
`4.1(3k)`	affected	—
`4.0(4o)`	affected	—
`4.2(2e)`	affected	—
`4.2(3d)`	affected	—
`4.2(3e)`	affected	—
`4.2(3g)`	affected	—
`4.1(3l)`	affected	—
`4.3(2b)`	affected	—
`4.2(3h)`	affected	—
`4.2(3i)`	affected	—
`4.3(2c)`	affected	—
`4.1(3m)`	affected	—
`4.3(2e)`	affected	—
`4.3(3a)`	affected	—
`4.2(3j)`	affected	—
`4.3(3c)`	affected	—
`4.3(4a)`	affected	—
`4.2(3k)`	affected	—
`4.3(4b)`	affected	—
`4.3(4c)`	affected	—
`4.2(3l)`	affected	—
`4.3(4d)`	affected	—
`4.3(2f)`	affected	—
`4.2(3m)`	affected	—
`4.3(5a)`	affected	—
`4.3(4e)`	affected	—
`4.1(3n)`	affected	—
`4.3(4f)`	affected	—
`4.2(3n)`	affected	—
`4.3(5c)`	affected	—
`4.2(3o)`	affected	—
`4.3(5d)`	affected	—
`4.3(6a)`	affected	—
`4.3(6b)`	affected	—
`4.3(5e)`	affected	—
`4.3(6c)`	affected	—
`4.2(3p)`	affected	—
`6.0(1b)`	affected	—
`6.0(1c)`	affected	—
`4.3(6d)`	affected	—
`6.0(1d)`	affected	—
`6.0(1e)`	affected	—
`4.3(6e)`	affected	—
`6.0(1f)`	affected	—
`4.3(6f)`	affected	—
`6.0(2b)`	affected	—
`6.0(1h)`	affected	—
`4.2(3r)`	affected	—
`6.0(2c)`	affected	—
`4.3(6g)`	affected	—
`6.0(2d)`	affected	—
`4.3(6h)`	affected	—
`4.2(3s)`	affected	—
`4.3(6i)`	affected	—

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.326% probability within 30 days)

Exploitation none

Automatable no

Technical Impact total

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-nxosw1-cWzSbtR
https://www.cve.org/Media/News/item/blog/2026/06/16/Preserving-Vulnerability-Level-Identification

History

Nov 7, 2026 6:30 PM Added references View changes

Type	Values Removed	Values Added
References		https://www.cve.org/Media/News/item/blog/2026/06/16/Preserving-Vulnerability-Level-Identification

Oct 9, 2026 1:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics	cvssV3_1 `{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}`	cvssV3_1 `{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}`

Oct 7, 2026 6:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Oct 7, 2026 4:30 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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.
Title		Cisco NX-OS Software Security Hardening Release: October 2026 - Out-of-bounds Write Vulnerabilities
Weaknesses		CWE-787
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-nxosw1-cWzSbtR
Metrics		cvssV3_1 `{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}`