Vulnerability · Published Oct 27, 2021 · Assigned by cisco

CVE-2021-34793Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Transparent Mode Denial of Service Vulnerability

High 8.6

In plain English

A high-severity security flaw in Cisco Adaptive Security Appliance (ASA) Software from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).

Severity (CVSS 3.1)8.6High

Exploit odds (30 days)0.6%top 51.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
Cisco	Cisco Adaptive Security Appliance (ASA) Software	n/a

Weakness: CWE-924 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

References

20211027 Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Transparent Mode Denial of Service Vulnerability vendor-advisory, x_refsource_CISCO