VULNERABILITY INTELLIGENCE

CVE-2021-34793

CVSS score8.6 HIGH
EPSS probability0.59%
CISA KEVNot currently listed
Published2021-10-27
Last modified2026-08-11
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

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.

Weakness classification

  • psirt@cisco.com: CWE-924
  • nvd@nist.gov: CWE-924

Primary references