CVE-2021-34793
8.6 · HIGHOverview
CVE-2021-34793 is a high-severity vulnerability affecting cisco adaptive_security_appliance. It was published on October 27, 2021 and has a CVSS 3.1 base score of 8.6 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.6, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from cisco. Update adaptive_security_appliance to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| cisco | adaptive_security_appliance | >= 0, < 9.8.4.40 | Affected |
| cisco | secure_firewall_threat_defense | >= 0, < 6.4.0.13 | Affected |
| cisco | adaptive_security_appliance_software | >= 9.9.0, < 9.12.4.29 | Affected |
Frequently Asked Questions
What is CVE-2021-34793?
CVE-2021-34793 is a high-severity vulnerability affecting cisco adaptive_security_appliance. It was published on October 27, 2021 and has a CVSS 3.1 base score of 8.6 (HIGH).
How severe is CVE-2021-34793?
This vulnerability has a CVSS 3.1 base score of 8.6, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-34793?
Check the references section for vendor advisories and patches from cisco. Update adaptive_security_appliance to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-34793?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-34793 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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Browser-based exploitation validates findings with real proof-of-concept.
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