cisco ios CVE-2021-1620 is a vulnerability in Cisco Internetwork Operating System (IOS)
Published on September 23, 2021

Cisco IOS and IOS XE Software IKEv2 AutoReconnect Feature Denial of Service Vulnerability
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.

Vendor Advisory NVD

Vulnerability Analysis

CVE-2021-1620 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
CHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Weakness Type

What is an Unused Variable Vulnerability?

The variable's value is assigned but never used, making it a dead store. After the assignment, the variable is either assigned another value or goes out of scope. It is likely that the variable is simply vestigial, but it is also possible that the unused variable points out a bug.

CVE-2021-1620 has been classified to as an Unused Variable vulnerability or weakness.


Products Associated with CVE-2021-1620

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Affected Versions

Cisco IOS Version n/a is affected by CVE-2021-1620

Exploit Probability

EPSS
0.33%
Percentile
55.49%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.