EN

CVE-2025-20191

High
7.4
0.05.010.0
Year
2025
Published
May 7, 2025
Known Affected Devices
0
CVSS Score
7.4

What is CVE-2025-20191?

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.

CVSS Vector Breakdown

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

Exploitable from an adjacent network (e.g. same LAN, Wi-Fi segment, Bluetooth).

AC
Attack Complexity
Low

No special conditions required. Exploit can be performed reliably and repeatedly.

PR
Privileges Required
None

No authentication required. Any anonymous user can exploit this vulnerability.

UI
User Interaction
None

No user interaction required. Exploit runs without any victim action.

S
Scope
Changed

Exploiting the vulnerability can affect other components beyond the vulnerable one.

C
Confidentiality Impact
None

No confidentiality impact. Sensitive data is not exposed.

I
Integrity Impact
None

No integrity impact. Data cannot be modified.

A
Availability Impact
High

Complete denial of service. The component becomes fully unavailable.

Known Affected Devices

Cisco Cisco Catalyst 9500-24Y4C

FAQ

How severe is CVE-2025-20191?

CVE-2025-20191 has a CVSS score of 7.4/10, rated as High. This is a high severity vulnerability and should be patched as soon as possible.

What does the CVSS score mean for CVE-2025-20191?

CVSS (Common Vulnerability Scoring System) rates vulnerability severity from 0.0 to 10.0. CVE-2025-20191 scores 7.4/10 (High). Scores 9.0–10.0 are Critical, 7.0–8.9 are High, 4.0–6.9 are Medium, and below 4.0 are Low.

Which devices are affected by CVE-2025-20191?

The list of devices confirmed to be affected by CVE-2025-20191 is shown in the "Affected Devices" section above. Check your firmware version against the vendor security advisory and apply the latest patch.

How do I fix or mitigate CVE-2025-20191?

Apply the latest firmware or software update from the vendor. Check the References section above for official advisories and patch notes. If no patch is available, consider disabling the affected feature or isolating the device from untrusted networks.