Cisco Secure Firewall Threat Defense
CVE-2020-3191
A vulnerability in DNS over IPv6 packet processing for Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to unexpectedly reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper length validation of a field in an IPv6 DNS packet. An attacker could exploit this vulnerability by sending a crafted DNS query over IPv6, which traverses the affected device. An exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. This vulnerability is specific to DNS over IPv6 traffic only.
What this means for your business
- It affects Cisco Secure Firewall Threat Defense. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 2% chance of attack attempts being seen in the next 30 days, ranking above 77% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Cisco Secure Firewall Threat Defense, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Not sure if your company is exposed?
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Scoring
- CVSS
- 8.6 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H- Weakness
- CWE-20
- Assigned by
- psirt@cisco.com
Dates
- Published
- 2020-05-06
- Last modified
- 2026-08-11
- Sources
- NVD
Affected products
- Cisco Secure Firewall Threat Defense6.2.3 - 6.2.3.16, 6.3.0 - 6.3.0.6, 6.4.0 - 6.4.0.6
- Cisco Asa 5505 Firmware9.4\(1\), 96.4\(0.42\)
- Cisco Asa 5505all versions
- Cisco Asa 5510 Firmware9.4\(1\), 96.4\(0.42\)
- Cisco Asa 5510all versions
- Cisco Asa 5512-X Firmware9.4\(1\), 96.4\(0.42\)
- Cisco Asa 5512-Xall versions
- Cisco Asa 5515-X Firmware9.4\(1\), 96.4\(0.42\)
- Cisco Asa 5515-Xall versions
- Cisco Asa 5520 Firmware9.4\(1\), 96.4\(0.42\)
- Cisco Asa 5520all versions
- Cisco Asa 5525-X Firmware9.4\(1\), 96.4\(0.42\)
As listed in the NVD configuration data. Not a statement about your estate.