CVE-2026-20043
Multiple Cisco Products Snort 3 Software Hardening Release: October 2026
No known exploitation. EPSS puts it in the 30th percentile. No fix published yet.
What to do
No fixed build or workaround is published yet. Limit exposure and watch for a patch.
- Cisco Cyber VisionAffected: 3.0.0Upgrade to: not statedAffected: 3.0.2Upgrade to: not statedAffected: 3.0.3Upgrade to: not statedAffected: 3.0.1Upgrade to: not stated + 61 more branchesStated by: CVE record
- Cisco Open Source Snort3Affected: 3.12.2.0Upgrade to: not statedAffected: 3.1.2.0Upgrade to: not statedAffected: 3.1.3.0Upgrade to: not statedAffected: 3.1.4.0Upgrade to: not stated + 101 more branchesStated by: CVE record
- Cisco Secure Firewall Threat Defense SoftwareAffected: 7.0.0Upgrade to: not statedAffected: 7.0.0.1Upgrade to: not statedAffected: 7.0.1Upgrade to: not statedAffected: 7.0.1.1Upgrade to: not stated + 55 more branchesStated by: CVE record
- Cisco UTD SNORT IPS Engine SoftwareAffected: 17.3.1aUpgrade to: not statedAffected: 17.3.2Upgrade to: not statedAffected: 17.4.1aUpgrade to: not statedAffected: 17.5.1Upgrade to: not stated + 79 more branchesStated by: CVE record
Versions as the sources state them. Full version matrix after sign-in
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.4% chance of exploitation activity in the next 30 days, which ranks it in the 30th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
6 events over 5 days, from the signal feeds we watch.
- Record updated
- Record updatedrecord updated
- Publishedweakness classified, att&ck mapped
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Scored 9.0 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- Initial AccessT1190Exploit Public-Facing Applicationhigh confidence
- Privilege EscalationT1068Exploitation for Privilege Escalationhigh confidence
Sources
Watch the software you run.
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