VDB-183243 · CVE-2021-1620 · GCVE-0-2021-1620

Cisco IOS/IOS XE IKEv2 denial of service

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.2	$0-$5k	0.00

Summaryinfo

A vulnerability marked as problematic has been reported in Cisco IOS and IOS XE. Impacted is an unknown function of the component IKEv2 Handler. Performing a manipulation results in denial of service. This vulnerability was named CVE-2021-1620. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Cisco IOS and IOS XE (Router Operating System) (the affected version is unknown). This affects an unknown code of the component IKEv2 Handler. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability.

The weakness was presented 09/23/2021 as cisco-sa-ikev2-ebFrwMPr. It is possible to read the advisory at tools.cisco.com. This vulnerability is uniquely identified as CVE-2021-1620 since 11/13/2020. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Router Operating System

Vendor

Cisco

Name

License

commercial

Website

Vendor: https://www.cisco.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.2

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.7
NVD Vector: 🔍

CNA Base Score: 7.7
CNA Vector (Cisco Systems, Inc.): 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Timelineinfo

11/13/2020 🔍
09/23/2021 +313 days 🔍
09/23/2021 +0 days 🔍
09/11/2025 +1449 days 🔍

Sourcesinfo

Vendor: cisco.com

Advisory: cisco-sa-ikev2-ebFrwMPr
Status: Confirmed

CVE: CVE-2021-1620 (🔍)
GCVE (CVE): GCVE-0-2021-1620
GCVE (VulDB): GCVE-100-183243
scip Labs: https://www.scip.ch/en/?labs.20150108

Entryinfo

Created: 09/23/2021 12:22
Updated: 09/11/2025 16:53
Changes: 09/23/2021 12:22 (49), 10/01/2021 14:24 (1), 09/11/2025 16:53 (33)
Complete: 🔍
Cache ID: 216::103