CVE-2026-20303: Cisco Catalyst SD-WAN Security Hardening Release - Input Validation Vulnerabilities
Cisco · Cisco Catalyst SD-WAN Controller
No fix listed · Affected: Cisco Catalyst SD-WAN Controller · Exploitation: public proof of concept (unverified)
ExploitationProof of concept public
Not in CISA KEV as of catalogue 2026.11.13 (13 Nov)
- In CISA KEV: not seen
- Exploited (reported): not seen
- Scanning observed: not seen
- Proof of concept public1 public GitHub repository (unverified), listed by PoC-in-GitHub27 Aug
- Not established: not seen
Higher than 42% of scored CVEs
DescriptionNVD
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.
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- Cisco
- Published
- August 2026
What changed
- PoC-in-GitHub lists 1 public GitHub repository (unverified) PoC-in-GitHub
Coverage1 article · 1 outlet
First in our coverage: SecurityWeek, 6 Aug.
- Cisco fixes critical flaws in Catalyst SDWAN and firewall gearSecurityWeek · first in our coverage
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