Vulnerability Monitor

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CVE-2021-34793


A vulnerability in the TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software operating in transparent mode could allow an unauthenticated, remote attacker to poison MAC address tables, resulting in a denial of service (DoS) vulnerability. This vulnerability is due to incorrect handling of certain TCP segments when the affected device is operating in transparent mode. An attacker could exploit this vulnerability by sending a crafted TCP segment through an affected device. A successful exploit could allow the attacker to poison the MAC address tables in adjacent devices, resulting in network disruption.


Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 8.6, indicating it can be exploited remotely over the network 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 19 products from cisco, from cisco, from cisco and 16 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

2021-10-27T19:15:08.563

Last Modified

2024-11-21T06:11:13.063

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 8.6 (HIGH)

CVSSv2 Vector

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

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

10.0

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-924
  • Type: Primary
    CWE-924

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application cisco adaptive_security_appliance < 9.8.4.40 Yes
Application cisco firepower_threat_defense < 6.4.0.13 Yes
Application cisco firepower_threat_defense < 6.6.5 Yes
Application cisco firepower_threat_defense < 6.7.0.3 Yes
Operating System cisco adaptive_security_appliance_software < 9.12.4.29 Yes
Operating System cisco adaptive_security_appliance_software < 9.14.3.9 Yes
Operating System cisco adaptive_security_appliance_software < 9.15.1.17 Yes
Operating System cisco adaptive_security_appliance_software < 9.16.2.3 Yes
Operating System cisco asa_5512-x_firmware 009.008\(004.025\) Yes
Hardware cisco asa_5512-x - No
Operating System cisco asa_5505_firmware 009.008\(004.025\) Yes
Hardware cisco asa_5505 - No
Operating System cisco asa_5515-x_firmware 009.008\(004.025\) Yes
Hardware cisco asa_5515-x - No
Operating System cisco asa_5525-x_firmware 009.008\(004.025\) Yes
Hardware cisco asa_5525-x - No
Operating System cisco asa_5545-x_firmware 009.008\(004.025\) Yes
Hardware cisco asa_5545-x - No
Operating System cisco asa_5555-x_firmware 009.008\(004.025\) Yes
Hardware cisco asa_5555-x - No
Operating System cisco asa_5580_firmware 009.008\(004.025\) Yes
Hardware cisco asa_5580 - No
Operating System cisco asa_5585-x_firmware 009.008\(004.025\) Yes
Hardware cisco asa_5585-x - 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.