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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.67%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 8.6 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
- EPSS
- 0.67% probability · 50th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-924
- Affected
- cisco/adaptive security appliance · cisco/secure firewall threat defense · cisco/adaptive security appliance software · cisco/asa 5512-x firmware · cisco/asa 5505 firmware · cisco/asa 5515-x firmware · cisco/asa 5525-x firmware · cisco/asa 5545-x firmware · cisco/asa 5555-x firmware · cisco/asa 5580 firmware · cisco/asa 5585-x firmware
- Source
- psirt@cisco.com
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.