#VU108841 Buffer Access with Incorrect Length Value in Cisco Systems, Inc products - CVE-2025-20191

Vulnerability identifier: #VU108841

Vulnerability risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-20191

CWE-ID: CWE-805

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Cisco IOS
Operating systems & Components / Operating system
Cisco IOS XE
Operating systems & Components / Operating system
Cisco NX-OS
Operating systems & Components / Operating system
Cisco Wireless LAN Controller (WLC) AireOS Software
Hardware solutions / Firmware

Vendor: Cisco Systems, Inc

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to the incorrect handling of DHCPv6 packets in the Switch Integrated Security Features (SISF). A remote attacker on the local network can send a specially crafted DHCPv6 packet and cause a denial of service condition on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Cisco IOS: All versions

Cisco IOS XE: 16.12.1

Cisco NX-OS: 7.0(3)I7(2) - 10.4(3)

Cisco Wireless LAN Controller (WLC) AireOS Software: 8.10.190.0

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

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.