Vulnerability Monitor

The vendors, products, and vulnerabilities you care about

CVE-2021-1621


A vulnerability in the Layer 2 punt code of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a queue wedge on an interface that receives specific Layer 2 frames, resulting in a denial of service (DoS) condition. This vulnerability is due to improper handling of certain Layer 2 frames. An attacker could exploit this vulnerability by sending specific Layer 2 frames on the segment the router is connected to. A successful exploit could allow the attacker to cause a queue wedge on the interface, resulting in a DoS condition.


Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.4, indicating it requires adjacent network access with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 45 products from cisco, from cisco, from cisco and 42 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2021-09-23T03:15:13.210

Last Modified

2024-11-21T05:44:45.667

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 7.4 (HIGH)

CVSSv2 Vector

AV:A/AC:L/Au:N/C:N/I:N/A:P

  • Access Vector: ADJACENT_NETWORK
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: PARTIAL
Exploitability Score

6.5

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-399
  • Type: Primary
    NVD-CWE-noinfo

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System cisco ios_xe < 17.3.1 Yes
Hardware cisco 1000_integrated_services_router - No
Hardware cisco 1100-4g\/6g_integrated_services_router - No
Hardware cisco 1100-4p_integrated_services_router - No
Hardware cisco 1100-8p_integrated_services_router - No
Hardware cisco 1100_integrated_services_router - No
Hardware cisco 1101-4p_integrated_services_router - No
Hardware cisco 1101_integrated_services_router - No
Hardware cisco 1109-2p_integrated_services_router - No
Hardware cisco 1109-4p_integrated_services_router - No
Hardware cisco 1109_integrated_services_router - No
Hardware cisco 1111x-8p_integrated_services_router - No
Hardware cisco 1111x_integrated_services_router - No
Hardware cisco 111x_integrated_services_router - No
Hardware cisco 1120_integrated_services_router - No
Hardware cisco 1160_integrated_services_router - No
Operating System cisco ios_xe < 17.3.1 Yes
Hardware cisco 4000_integrated_services_router - No
Hardware cisco 4221_integrated_services_router - No
Hardware cisco 4321_integrated_services_router - No
Hardware cisco 4331_integrated_services_router - No
Hardware cisco 4351_integrated_services_router - No
Hardware cisco 4431_integrated_services_router - No
Hardware cisco 4451-x_integrated_services_router - No
Hardware cisco 4451_integrated_services_router - No
Hardware cisco 4461_integrated_services_router - No
Operating System cisco ios_xe < 17.3.1 Yes
Hardware cisco asr_1000 - No
Hardware cisco asr_1000-x - No
Hardware cisco asr_1001 - No
Hardware cisco asr_1001-hx - No
Hardware cisco asr_1001-hx_r - No
Hardware cisco asr_1001-x - No
Hardware cisco asr_1001-x_r - No
Hardware cisco asr_1002 - No
Hardware cisco asr_1002-hx - No
Hardware cisco asr_1002-hx_r - No
Hardware cisco asr_1002-x - No
Hardware cisco asr_1002-x_r - No
Hardware cisco asr_1004 - No
Hardware cisco asr_1006 - No
Hardware cisco asr_1006-x - No
Hardware cisco asr_1009-x - No
Hardware cisco asr_1013 - No
Hardware cisco asr_1023 - No
Operating System cisco ios_xe < 17.3.1 Yes
Hardware cisco csr_1000v - No
Operating System cisco ios_xe < 17.3.1 Yes
Hardware cisco isrv - No

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For cisco's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.