Vulnerability Monitor

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CVE-2021-1356


Multiple vulnerabilities in the web UI of Cisco IOS XE Software could allow an authenticated, remote attacker with read-only privileges to cause the web UI software to become unresponsive and consume vty line instances, resulting in a denial of service (DoS) condition. These vulnerabilities are due to insufficient error handling in the web UI. An attacker could exploit these vulnerabilities by sending crafted HTTP packets to an affected device. A successful exploit could allow the attacker to cause the web UI software to become unresponsive and consume all available vty lines, preventing new session establishment and resulting in a DoS condition. Manual intervention would be required to regain web UI and vty session functionality. Note: These vulnerabilities do not affect the console connection.


Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 4.3, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts and limited availability for affected systems. Impacting 1 product from cisco 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

2021-03-24T21:15:11.647

Last Modified

2024-11-21T05:44:10.107

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 4.3 (MEDIUM)

CVSSv2 Vector

AV:N/AC:M/Au:S/C:N/I:N/A:P

  • Access Vector: NETWORK
  • Access Complexity: MEDIUM
  • Authentication: SINGLE
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: PARTIAL
Exploitability Score

6.8

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-20
  • Type: Primary
    CWE-755

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System cisco ios_xe 3.15.1xbs Yes
Operating System cisco ios_xe 3.15.2xbs Yes
Operating System cisco ios_xe 17.1.1 Yes
Operating System cisco ios_xe 17.1.1a Yes
Operating System cisco ios_xe 17.1.1s Yes
Operating System cisco ios_xe 17.1.1t Yes
Operating System cisco ios_xe 17.1.2 Yes
Operating System cisco ios_xe 17.2.1 Yes
Operating System cisco ios_xe 17.2.1a Yes
Operating System cisco ios_xe 17.2.1r Yes
Operating System cisco ios_xe 17.2.1v Yes
Operating System cisco ios_xe 17.2.2 Yes
Operating System cisco ios_xe 17.2.3 Yes

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.