What is the CVSS score of CVE-2026-20033?

CVE-2026-20033 has a CVSS 3.1 base score of 7.4 (High). CVSS vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H. EPSS exploitation probability: 0.0%.

How to fix or mitigate CVE-2026-20033?

Within 24 hours: Inventory all Nexus 9000 switches in ACI mode and assess criticality of each. Within 7 days: Implement network segmentation to restrict management access and monitor for suspicious activity; enable enhanced logging on affected devices. Within 30 days: Establish vendor communication protocol for patch availability and develop change management plan for deployment once patches release.

Cisco CVE-2026-20033

HIGH

Buffer Access with Incorrect Length Value (CWE-805)

2026-02-25 psirt@cisco.com

Denial Of Service Cisco

7.4

CVSS 3.1 · NVD

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Send crafted Ethernet frame to management interface
Exploit

Trigger insufficient validation in frame processor
Execution

Cause unexpected device reload
Impact

Denial of service

Vulnerability Assessment

Weakness	CWE CWE-805 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Buffer access bounds checking
Exploitation Conditions	Direct network access to out-of-band (OOB) management interface of Cisco Nexus 9000 Series Switch in ACI mode. Attacker must be on same layer 2 network segment (adjacent network).
Impact	CVSS 7.4 (HIGH). Attack vector: Adjacent Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation no authentication required.
Exploit ScenarioDerived	An attacker without authentication could exploit this vulnerability to cause the device to reload unexpectedly, resulting in a DoS condition.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Cisco Nexus 9000 Series Fabric Switches in ACI mode contains a vulnerability that allows attackers to cause the device to reload unexpectedly, resulting in a DoS condition (CVSS 7.4).

RemediationAI

Monitor vendor advisories for a patch.

Affected ProductsAI

Product: Cisco Nexus 9000 Series Fabric Switches in ACI mode.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

affects Cisco Nexus 9000 Series Fabric Switches in ACI mode. in Cisco Nexus 9000 Series Fabric Switches in ACI mode could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to insufficient validation when processing specific Ethernet frames. An attacker could exploit this vulnerability by sending a crafted Ethernet frame to the management interface of an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, re

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.4 HIGH

AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

DescriptionCVE.org

A vulnerability in Cisco Nexus 9000 Series Fabric Switches in ACI mode could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.

Executive ViewAI

Why It Matters

Cisco Nexus 9000 Series switches running ACI mode are vulnerable to denial-of-service attacks that force device reloads, potentially disrupting network fabric operations and connected services. Organizations using these switches require immediate mitigation planning since vendor patches are not yet available.

Business Impact: High

Compensating Controls

Restrict management access to Nexus 9000 devices via network segmentation and firewall rules; implement strict change control and monitoring for ACI fabric operations; configure redundancy and failover mechanisms to minimize impact of unexpected reloads; enable syslog alerting for device reload events; consider load balancing traffic across multiple fabric nodes to reduce single-point-of-failure risk until patch availability.

Threat Intelligence Overview

EPSS Score

0.0%

Top 96% exploitable

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 0.0%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.