Secure Firewall ASA and FTD
CVE-2026-20053: Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Heap Overflow Denial of Service Vulnerability
Multiple Cisco products are affected by a vulnerability in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash.
Published
ExploitedNot in CISA KEV
Ransomware useNot reportedPer CISA
SeverityMEDIUMCVSS 3.1 5.8
EPSS0.43%Chance of exploitation in 30 days
Public exploitNot tracked
FixNot yet
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Cisco Cyber Vision 3.0 | See the advisory |
| Cisco Cyber Vision 3.0 | See the advisory |
| Cisco Cyber Vision 3.0 | See the advisory |
| Cisco Cyber Vision 3.0 | See the advisory |
| Cisco Cyber Vision 3.1 | See the advisory |
| Cisco Cyber Vision 3.0 | See the advisory |
| Cisco Cyber Vision 3.1 | See the advisory |
| Cisco Cyber Vision 3.1 | See the advisory |
| Cisco Cyber Vision 3.2 | See the advisory |
| Cisco Cyber Vision 3.0 | See the advisory |
| Cisco Cyber Vision 3.2 | See the advisory |
| Cisco Cyber Vision 3.0 | See the advisory |
| Cisco Cyber Vision 3.2 | See the advisory |
| Cisco Cyber Vision 3.2 | See the advisory |
| Cisco Cyber Vision 3.2 | See the advisory |
| Cisco Cyber Vision 4.0 | See the advisory |
| Cisco Cyber Vision 4.0 | See the advisory |
| Cisco Cyber Vision 4.0 | See the advisory |
| Cisco Cyber Vision 4.0 | See the advisory |
| Cisco Cyber Vision 4.1 | See the advisory |
| Cisco Cyber Vision 4.1 | See the advisory |
| Cisco Cyber Vision 4.1 | See the advisory |
| Cisco Cyber Vision 4.1 | See the advisory |
| Cisco Cyber Vision 4.1 | See the advisory |
| Cisco Cyber Vision 4.2 | See the advisory |
| Cisco Cyber Vision 4.2 | See the advisory |
| Cisco Cyber Vision 4.1 | See the advisory |
| Cisco Cyber Vision 4.2 | See the advisory |
| Cisco Cyber Vision 4.2 | See the advisory |
| Cisco Cyber Vision 4.2 | See the advisory |
| Cisco Cyber Vision 4.2 | See the advisory |
| Cisco Cyber Vision 4.2 | See the advisory |
| Cisco Cyber Vision 4.1 | See the advisory |
| Cisco Cyber Vision 4.3 | See the advisory |
| Cisco Cyber Vision 4.3 | See the advisory |
| Cisco Cyber Vision 4.3 | See the advisory |
| Cisco Cyber Vision 4.3 | See the advisory |
| Cisco Cyber Vision 4.4 | See the advisory |
| Cisco Cyber Vision 4.4 | See the advisory |
| Cisco Cyber Vision 4.4 | See the advisory |
| Cisco Cyber Vision 4.4 | See the advisory |
| Cisco Cyber Vision 4.1 | See the advisory |
| Cisco Cyber Vision 5.0 | See the advisory |
| Cisco Cyber Vision 5.0 | See the advisory |
| Cisco Cyber Vision 5.0 | See the advisory |
| Cisco Cyber Vision 5.1 | See the advisory |
| Cisco Cyber Vision 5.1 | See the advisory |
| Cisco Cyber Vision 5.1 | See the advisory |
| Cisco Cyber Vision 5.1 | See the advisory |
| Cisco Cyber Vision 5.2 | See the advisory |
| Cisco Cyber Vision 5.2 | See the advisory |
| Cisco Cyber Vision 5.3 | See the advisory |
| Cisco Cyber Vision 5.3 | See the advisory |
| Cisco Cyber Vision 5.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.3 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.6 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.7 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.6 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.6 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.7 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.6 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.7 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.2 | See the advisory |
| Cisco Secure Firewall Threat Defense (FTD) Software 7.4 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.9 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.13 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.14 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.15 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.16 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.9 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.15 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.15 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.17 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.15 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.15 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.15 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.18 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.18 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.15 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.12 | See the advisory |
| Cisco UTD SNORT IPS Engine Software 17.18 | See the advisory |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
Multiple Cisco products are affected by a vulnerability in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash.
This vulnerability is due to improper range checking when decompressing VBA data, which is user controlled. An attacker could exploit this vulnerability by sending crafted VBA data to the Snort 3 Detection Engine on the targeted device. A successful exploit could allow the attacker to cause an overflow of heap data, which could cause a DoS condition.
Exploitation
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 11 Oct 2026.