CVE-2026-20303 — CRITICAL (9.9)

Vulnerability 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.

CVSS Score

9.9

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Related Weaknesses (CWE)

CWE-20

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/ci

FAQ

What is CVE-2026-20303?

CVE-2026-20303 is a vulnerability with a CVSS score of 9.9 (CRITICAL). 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...

How severe is CVE-2026-20303?

CVE-2026-20303 has been rated CRITICAL with a CVSS base score of 9.9/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-20303?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.