Vulnerability · Published Aug 5, 2026 · Assigned by cisco
CVE-2026-20303Cisco Catalyst SD-WAN Security Hardening Release - Input Validation Vulnerabilities
Critical 9.9
In plain English
A critical-severity improper input validation in Cisco Catalyst SD-WAN Controller from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Catalyst SD-WAN 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-2026-20303 are related to improper input validation issues that are grouped under the Common Weakness Enumeration (CWE) CWE-20.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco Catalyst SD-WAN Controller | 20.6.420.9.220.3.620.7.220.7.120.5.120.6.219.3.0 |
| Cisco | Cisco Catalyst SD-WAN Manager | 20.1.1219.2.118.4.418.4.520.1.1.120.1.119.3.019.2.2 |
Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H