CVE-2021-34793

high Cisco
CVSS v3 Base Score
8.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score
0.6%
Exploitation probability in 30 days
Top 52% most likely to be exploited
Attack Characteristics
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
High
Published: October 27, 2021 (1775 days ago)
Last Modified: August 11, 2026
Vendor: Cisco
Source: NVD

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.

CWE

CWE-924

Affected Products

cisco adaptive security appliancecisco secure firewall threat defensecisco adaptive security appliance softwarecisco asa 5512-x firmwarecisco asa 5505 firmwarecisco asa 5515-x firmwarecisco asa 5525-x firmwarecisco asa 5545-x firmwarecisco asa 5555-x firmwarecisco asa 5580 firmware

References

🔗 tools.cisco.com 🔗 tools.cisco.com