Vulnerability · Published Oct 21, 2026 · Assigned by cisco
CVE-2026-20043Multiple Cisco Products Snort 3 Software Hardening Release: October 2026
Critical 9.0
In plain English
A critical-severity out-of-bounds write in Cisco Cyber Vision from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco Cyber Vision | 3.0.03.0.23.0.33.0.13.1.03.0.43.1.13.1.2 |
| Cisco | Cisco Open Source Snort3 | 3.12.2.03.1.2.03.1.3.03.1.4.03.1.5.03.1.6.03.1.7.03.1.8.0 |
| Cisco | Cisco Secure Firewall Threat Defense (FTD) Software | 7.0.07.0.0.17.0.17.0.1.17.0.27.0.2.17.0.37.2.0.1 |
| Cisco | Cisco UTD SNORT IPS Engine Software | 17.3.1a17.3.217.4.1a17.5.117.3.317.5.1a17.3.417.3.4a |
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H