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HIGH · 8.6

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, remo...

Vulnerability Description

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.

CVSS Score

8.6

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
CiscoAdaptive Security Appliance< 9.8.4.40
CiscoFirepower Threat Defense< 6.4.0.13
CiscoAdaptive Security Appliance Software>= 9.9.0, < 9.12.4.29
CiscoAsa 5512-X Firmware009.008\(004.025\)
CiscoAsa 5512-X-
CiscoAsa 5505 Firmware009.008\(004.025\)
CiscoAsa 5505-
CiscoAsa 5515-X Firmware009.008\(004.025\)
CiscoAsa 5515-X-
CiscoAsa 5525-X Firmware009.008\(004.025\)
CiscoAsa 5525-X-
CiscoAsa 5545-X Firmware009.008\(004.025\)
CiscoAsa 5545-X-
CiscoAsa 5555-X Firmware009.008\(004.025\)
CiscoAsa 5555-X-
CiscoAsa 5580 Firmware009.008\(004.025\)
CiscoAsa 5580-
CiscoAsa 5585-X Firmware009.008\(004.025\)
CiscoAsa 5585-X-

Related Weaknesses (CWE)

CWE-924

References

FAQ

What is CVE-2021-34793?

CVE-2021-34793 is a vulnerability with a CVSS score of 8.6 (HIGH). 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, remo...

How severe is CVE-2021-34793?

CVE-2021-34793 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2021-34793?

Check the references section above for vendor advisories and patch information. Affected products include: Cisco Adaptive Security Appliance, Cisco Firepower Threat Defense, Cisco Adaptive Security Appliance Software, Cisco Asa 5512-X Firmware, Cisco Asa 5512-X.