Vulnerability · Published Sep 23, 2021 · Assigned by cisco

CVE-2021-1620Cisco IOS and IOS XE Software IKEv2 AutoReconnect Feature Denial of Service Vulnerability

High 7.7

In plain English

A high-severity security flaw in Cisco IOS from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities).

Severity (CVSS 3.1)7.7High

Exploit odds (30 days)1.1%top 35.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) support for the AutoReconnect feature of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to exhaust the free IP addresses from the assigned local pool. This vulnerability occurs because the code does not release the allocated IP address under certain failure conditions. An attacker could exploit this vulnerability by trying to connect to the device with a non-AnyConnect client. A successful exploit could allow the attacker to exhaust the IP addresses from the assigned local pool, which prevents users from logging in and leads to a denial of service (DoS) condition.

Affected products (as reported)

Vendor	Product	Versions
Cisco	Cisco IOS	n/a

Weakness: CWE-563 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

References

20210922 Cisco IOS and IOS XE Software IKEv2 AutoReconnect Feature Denial of Service Vulnerability vendor-advisory, x_refsource_CISCO