Medium 5.8Published Mar 4, 2026

CVE-2026-20053Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Heap Overflow Denial of Service Vulnerability

Updated under an hour ago (Oct 26, 2026, 11:00 PM ET)

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It affects Cisco Cyber Vision and 5 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Cisco Cyber Vision

Exploited in the last 30 days

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: 5.8 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Weakness (CWE): CWE-122
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: cisco
NVD analysis: Analyzed
Record last updated: Mar 4, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Cisco Cisco Cyber Vision cisco:cyber_vision (from the name)	3.0.0; 3.0.2; 3.0.3; 3.0.1; 3.1.0; 3.0.4; 3.1.1; 3.1.2; and 46 more ranges	CNA record
Cisco Cisco Secure Firewall Threat Defense (FTD) Software cisco:secure_firewall_threat_defense_ftd_software (from the name)	7.2.0; 7.2.0.1; 7.2.1; 7.3.0; 7.2.2; 7.2.3; 7.3.1; 7.2.4; and 29 more ranges	CNA record
Cisco Cisco UTD SNORT IPS Engine Software cisco:utd_snort_ips_engine_software (from the name)	17.12.1a; 17.9.4; 17.12.2; 17.13.1a; 17.12.3; 17.14.1a; 17.12.4; 17.12.3a; and 21 more ranges	CNA record
cisco snort cisco:snort	from 3.0.0-233 before 3.9.3.0	NVD
cisco cyber_vision cisco:cyber_vision	3.0.0; 3.0.1; 3.0.2; 3.0.3; 3.0.4; 3.0.5; 3.0.6; 3.1.0; and 45 more ranges	NVD
cisco secure_firewall_threat_defense cisco:secure_firewall_threat_defense	7.2.0; 7.2.0.1; 7.2.1; 7.2.2; 7.2.3; 7.2.4; 7.2.4.1; 7.2.5; and 29 more ranges	NVD
cisco unified_threat_defense_snort_intrusion_prevention_system_engine cisco:unified_threat_defense_snort_intrusion_prevention_system_engine	17.9.4; 17.9.5e; 17.12.1a; 17.12.2; 17.12.3; 17.12.3a; 17.12.4; 17.12.4a; and 21 more ranges	NVD

References

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-snort3-vbavuls-96UcVVed	vendor-advisory, mitigation

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.