---
id: CVE-2026-20303
title: >-
  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
summary: >-
  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 …
severity: critical
cvss: 9.9
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-20
published: '2026-08-05'
updated: '2026-08-14'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-20303'
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-sdwan-faLcR3K
    label: psirt@cisco.com
  - url: >-
      https://www.cve.org/Media/News/item/blog/2026/06/16/Preserving-Vulnerability-Level-Identification
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - exploit-available
epss: 0.00321
epssPercentile: 0.25347
ingestedAt: '2026-08-15T17:27:28.076Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/HORKimhab/Cisco-CVE-2026-20303-More'
  checkedAt: '2026-09-24T07:53:00.455Z'
exploitAvailable: true
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.