Medium severity · published Mar 4, 2026
CVE-2026-20054
Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Infinite Loop Denial of Service Vulnerability
5.8
CVSS
0.5%
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 error checking when decompressing VBA data. 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 the Snort 3 Detection Engine to enter an infinite loop, causing 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)0.5% · higher than 40% 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
3.17.1S; 16.12.3; Fuji-16.9.5; 16.12.4; 17.3.1a; 16.6.6; +34 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
3.17.0s; 3.17.1s; 16.6.1; 16.6.5; 16.6.6; 16.6.7a; +34 more · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-20054
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-20054
Vendor Advisory
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-snort3-vbavuls-96UcVVed
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