#VU56842 Input validation error

Published: 2021-09-23

Vulnerability identifier: #VU56842

Vulnerability risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-1620


Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Cisco IOS
Operating systems & Components / Operating system
Cisco IOS XE
Operating systems & Components / Operating system

Vendor: Cisco Systems, Inc


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

The vulnerability exists due to the code does not release the allocated IP address under certain failure conditions in the Internet Key Exchange Version 2 (IKEv2) support for the AutoReconnect feature. A remote authenticated attacker can try to connect to the device with a non-AnyConnect client and perform a denial of service (DoS) attack.

Install updates from vendor's website.

Vulnerable software versions

Cisco IOS: 16.9.6, 17.3.1a

Cisco IOS XE: 16.9.6, 17.3.1a


External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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

Latest bulletins with this vulnerability