Input validation error in Cisco Firewall Threat Defense (FTD) and Cisco Adaptive Security Appliance (ASA) - CVE-2021-1501
Published: April 28, 2021
Vulnerability identifier: #VU52717
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-1501
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to insufficient validation of user-supplied input in the SIP inspection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software. A remote attacker can pass specially crafted SIP packets to the system and perform a denial of service (DoS) attack.
Affected software
Cisco Firewall Threat Defense (FTD)
Cisco Adaptive Security Appliance (ASA)
Cisco Adaptive Security Appliance (ASA)
How to mitigate CVE-2021-1501
Install updates from vendor's website.
Cisco Firewall Threat Defense (FTD) - addressed in versions 6.4.0.12, 6.6.4, 6.7.0.2
Cisco Adaptive Security Appliance (ASA) - addressed in versions 9.8.4.35, 9.9.2.85, 9.12.4.18, 9.13.1.21, 9.14.2.13, 9.15.1.15
Cisco Adaptive Security Appliance (ASA) - addressed in versions 9.8.4.35, 9.9.2.85, 9.12.4.18, 9.13.1.21, 9.14.2.13, 9.15.1.15