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7.4

Cisco Switch Security Feature Fails to Handle DHCPv6 Packets

CVE-2025-20191 · published 1 year ago
Summary

A flaw in Cisco's Switch Integrated Security Features could allow an attacker to crash a device by sending a specific type of internet packet. This could cause the device to restart, making it unavailable. Cisco is working on a fix, but in the meantime, users should ensure their devices are updated with the latest security patches.

Original advisory text
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 a...
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.
References
Fix within
Internet-facing 60 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker partial control
Severity
7.4 High
Exploitation
<1% chance of attack within 30 days
Type
CWE-805Buffer Access with Incorrect Length Value
Timeline
Published7 May 2025
Updated4 Nov 2026
First seen7 Mar 2026
Sources
CVE-2025-20191 · NVD
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