#VU56842 Input validation error in Cisco IOS and Cisco IOS XE - CVE-2021-1620

Vulnerability identifier: #VU56842

Vulnerability risk: Medium

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

CVE-ID: CVE-2021-1620

CWE-ID: CWE-20

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

Description

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.

Mitigation
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

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External links
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ikev2-ebFrwMPr

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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.