CVE-2026-20048 Cisco NX-OS Software SNMP Denial of Service Vulnerability

What is CVE-2026-20048?

CVE-2026-20048 is a high-severity denial of service vulnerability in Cisco NX-OS System Software in ACI Mode, published on 25 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco Nexus 9000 Series Fabric Switches in ACI mode could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper processing when parsing SNMP requests. An attacker could exploit this vulnerability by continuously sending SNMP queries to a specific MIB of an affected device. A successful exploit could allow the attacker to cause a kernel panic on the device, resulting in a reload and a DoS condition. Note: This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMPv1 or SNMPv2c, the attacker must have a valid read-only SNMP community string for the affected system. To exploit this vulnerability through SNMPv3, the attacker must have valid SNMP user credentials for the affected system.

Weakness: CWE-789

Which versions are affected by CVE-2026-20048?

How do I fix CVE-2026-20048?

No fix has been published for CVE-2026-20048 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-20048 being exploited?

There is no known exploitation of CVE-2026-20048 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-c9vx-x9q2-ffx8.