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.

Classification

CVE ID: CVE-2025-20191

CVSS Base Severity: HIGH

CVSS Base Score: 7.4

CVSS Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Affected Products

Vendor: Cisco

Product: Cisco NX-OS Software, Cisco Wireless LAN Controller (WLC)

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.01% (probability of being exploited)

EPSS Percentile: 1.42% (scored less or equal to compared to others)

EPSS Date: 2025-06-03 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-20191
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sisf-dos-ZGwt4DdY

Timeline