Critical 9.0Published Oct 21, 2026

CVE-2026-20043Multiple Cisco Products Snort 3 Software Hardening Release: October 2026

Updated under an hour ago (Oct 27, 2026, 6:40 AM ET)

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It affects Cisco Cyber Vision and 3 other products. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.36%, higher than 30% of scored CVEs.

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Every CVE for Cisco Cyber Vision

Exploited in the last 30 days

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20043 are related to issues concerning out-of-bounds writes that are grouped under the Common Weakness Enumeration (CWE) Base CWE-787.

CVSS: 9.0 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Weakness (CWE): CWE-787
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.36% (percentile 30)
Assigned by: cisco
NVD analysis: Awaiting Analysis
Record last updated: Oct 22, 2026
First seen by InfoSec Signals: Oct 21, 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 57 more ranges	CNA record
Cisco Cisco Open Source Snort3 cisco:open_source_snort3 (from the name)	3.12.2.0; 3.1.2.0; 3.1.3.0; 3.1.4.0; 3.1.5.0; 3.1.6.0; 3.1.7.0; 3.1.8.0; and 97 more ranges	CNA record
Cisco Cisco Secure Firewall Threat Defense (FTD) Software cisco:secure_firewall_threat_defense_ftd_software (from the name)	7.0.0; 7.0.0.1; 7.0.1; 7.0.1.1; 7.0.2; 7.0.2.1; 7.0.3; 7.2.0.1; and 51 more ranges	CNA record
Cisco Cisco UTD SNORT IPS Engine Software cisco:utd_snort_ips_engine_software (from the name)	17.3.1a; 17.3.2; 17.4.1a; 17.5.1; 17.3.3; 17.5.1a; 17.3.4; 17.3.4a; and 75 more ranges	CNA record

References

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-snort3-ybgmhTQe

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.