Medium severity · published Mar 4, 2026
CVE-2026-20053
Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Heap Overflow Denial of Service Vulnerability
5.8
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CC
Cisco Cyber Vision · Cisco
3.0.0; 3.0.2; 3.0.3; 3.0.1; 3.1.0; 3.0.4; +34 more · source: vendor
CS
Cisco Secure Firewall Threat Defense (FTD) Software · Cisco
7.2.0; 7.2.0.1; 7.2.1; 7.3.0; 7.2.2; 7.2.3; +31 more · source: vendor
CU
Cisco UTD SNORT IPS Engine Software · Cisco
17.12.1a; 17.9.4; 17.12.2; 17.13.1a; 17.12.3; 17.14.1a; +23 more · source: vendor
CV
Cyber Vision · Cisco
3.0.0; 3.0.1; 3.0.2; 3.0.3; 3.0.4; 3.0.5; +34 more · source: NVD
SF
Secure Firewall Threat Defense · Cisco
7.2.0; 7.2.0.1; 7.2.1; 7.2.2; 7.2.3; 7.2.4; +31 more · source: NVD
SN
Snort · Cisco
3.0.0-233 before 3.9.3.0 · source: NVD
UT
Unified Threat Defense Snort Intrusion Prevention System Engine · Cisco
17.9.4; 17.9.5e; 17.12.1a; 17.12.2; 17.12.3; 17.12.3a; +23 more · source: NVD
Affected product
CC
Cisco Cyber Vision
Cisco
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