Vulnerability in Cisco Nx-Os System Software In Aci Mode

CVE-2026-20033

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. 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, resulting in a DoS condition. Note: Only the out-of-band (OOB) management interface is affected.

EPSS: 0.002 (5.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-20033?
CVE-2026-20033 is a high-severity vulnerability in Cisco Nx-Os System Software In Aci Mode, classified under Buffer Access with Incorrect Length Value. CVSS score: 7.4/10. Published 2026-02-25.
How severe is CVE-2026-20033?
High severity. CVSS v3 base score is 7.4 out of 10.