Cisco NX-OS Software: Improper Access Control
CVE-2026-76455 is a critical-severity improper access control vulnerability in Cisco NX-OS Software from Cisco, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Cisco NX-OS Software versions: 8.2(5); 7.3(5)D1(1); 8.4(2), and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 4.01% chance of exploitation within 30 days, which is in the top 9.29% of all scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Cisco NX-OS Software you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco NX-OS Software | 8.2(5); 7.3(5)D1(1); 8.4(2); 8.4(3); 9.2(3); 8.2(1); 7.3(1)D1(1); 9.2(2v); and 32 more ranges | Not stated |
| Cisco | Cisco NX-OS System Software in ACI Mode | 15.2(1g); 15.2(2e); 15.2(2f); 15.2(2g); 15.2(2h); 15.2(3f); 15.2(3e); 15.2(3g); and 32 more ranges | Not stated |
| Cisco | Cisco Unified Computing System (Managed) | 4.0(1a); 4.1(1d); 4.0(4f); 4.0(4c); 4.0(2b); 4.1(2a); 4.0(4a); 4.0(4e); and 32 more ranges | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (cisco.com).
Official 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-2026-76455 are related to improper access control issues that are grouped under the Common Weakness Enumeration (CWE) CWE-284.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Access Control
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
How developers prevent this class of flaw
- Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Cisco NX-OS Software
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Improper Access Control vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 8.2 High severity
- 8.3 High severity
- 8.8 High severity
- 8.2 High severity
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