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Review reviewCritical

CVE-2026-20303

Cisco Cisco Catalyst SD-WAN Controller, Cisco Catalyst SD-WAN Manager

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
9.9
EPSS
0.29%
21.4% percentile
CISA KEV
Not listed
Published
2026.08.06
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.29%
Technical severityCVSS 9.9

Vulnerability 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.

Affected product and versions

Product
Cisco Cisco Catalyst SD-WAN Controller, Cisco Catalyst SD-WAN Manager
Affected versions
>= 20.6.4, >= 20.9.2, >= 20.3.6, >= 20.7.2, >= 20.7.1, >= 20.5.1, >= 20.6.2, >= 19.3.0, >= 20.6.1, >= 17.2.4, >= 18.2.0, >= 18.4.6, >= 19.1.0, >= 19.2.4, >= 19.2.929, >= 18.3.8, >= 18.4.303, >= 18.3.7, >= 18.4.1, >= 19.2.097
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Cisco Cisco Catalyst SD-WAN Controller, Cisco Catalyst SD-WAN Manager and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE
CWE-20