CVE-2021-34783

Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Software-Based SSL/TLS Denial of Service Vulnerability

Description

A vulnerability in the software-based SSL/TLS message handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL/TLS decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: Datagram TLS (DTLS) messages cannot be used to exploit this vulnerability.

Categories

8.6
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.30%
Vendor Advisory cisco.com
Affected: Cisco Cisco Adaptive Security Appliance (ASA) Software
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-34783?
CVE-2021-34783 has been scored as a high severity vulnerability.
How to fix CVE-2021-34783?
To fix CVE-2021-34783, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-34783 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-34783 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-34783?
CVE-2021-34783 affects Cisco Cisco Adaptive Security Appliance (ASA) Software.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.