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CVE-2026-20303: Improper Input Validation in Cisco Cisco Catalyst SD-WAN Controller

0
Critical
VulnerabilityCVE-2026-20303cvecve-2026-20303gcvecsafcve-2026-20304cve-2026-20310cve-2026-20312cve-2026-20313nationaal-cyber-security-centr
Published: 08/05/2026 (08/05/2026, 16:29:52 UTC)
Source: CVE Database V5
Vendor/Project: Cisco
Product: Cisco Catalyst SD-WAN Controller

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 v3.1

Score 9.9critical

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected software

Cisco

Cisco Catalyst SD-WAN Controller

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=19.2.0=19.2.099=18.3.6=20.4.2=19.0.0=20.9.1=20.3.5=20.3.1=18.3.5=20.6.3=18.4.3=18.4.4=18.3.3=17.2.8=20.8.1=19.2.32=19.2.2=17.2.5=18.4.0=20.4.1.1=20.1.3=20.1.2=17.2.10=19.2.098=20.1.1=17.2.6=19.2.1=18.3.4=20.4.1=17.2.9=19.2.31=19.0.1a=18.3.0=17.2.7=18.4.5=20.3.4=20.3.3=20.4.1.2=20.3.2=18.3.1=20.1.12=19.2.3=20.10.1=20.6.5=20.3.7=20.9.3=20.11.1=20.6.3.2=20.4.2.3=20.3.5.1=20.3.4.3=20.9.3.1=20.6.4.1=20.3.3.2=20.6.5.2=20.3.7.1=20.11.1.1=20.10.1.1=20.6.1.2=20.1.3.1=20.9.2.2=20.6.5.3=20.6.3.3=20.3.7.2=20.6.5.4=20.9.2.3=20.9.4=20.12.1=20.3.8=20.6.6=20.12.2=20.13.1=20.9.5=20.12.3=20.6.7=20.9.5.1=20.14.1=20.12.3.1=20.12.4=20.15.1=20.9.6=20.6.8=20.16.1=20.9.5.3=20.12.4.1=20.15.2=20.12.5=20.9.7=20.15.3=20.12.5.1=20.12.5.2=20.15.4=20.9.7.1=20.18.1=20.12.6=20.9.8=20.15.4.1=20.18.2=26.1.1=20.15.4.2=20.18.2.1=20.12.5.3=20.12.6.1=20.9.8.2=20.15.5=20.18.3=20.12.7=20.9.9=20.18.2.2=20.12.5.4=20.12.7.1=20.15.5.1=20.15.4.3=20.12.6.2=20.15.5.2=20.15.4.4=26.1.1.1=20.9.9.1=20.18.3.1=26.1.1.2=20.15.4.5=20.15.5.3=20.12.7.2=20.9.9.2=20.15.6

Cisco

Cisco Catalyst SD-WAN Manager

Affected versions
=20.1.12=19.2.1=18.4.4=18.4.5=20.1.1.1=20.1.1=19.3.0=19.2.2=19.2.099=18.3.6=18.3.7=19.2.0=18.3.8=19.0.0=19.1.0=18.4.302=18.4.303=19.2.097=19.2.098=17.2.10=18.3.6.1=19.0.1a=18.2.0=18.4.3=18.4.1=17.2.8=18.3.3.1=18.4.0=18.3.1=17.2.6=17.2.9=18.3.4=17.2.5=18.3.1.1=18.3.5=18.4.0.1=18.3.3=17.2.7=17.2.4=18.3.0=19.2.3=18.4.501_ES=20.3.1=20.1.2=19.2.929=19.2.31=20.3.2=19.2.32=20.3.2_925=20.3.2.1=20.3.2.1_927=18.4.6=20.1.2_937=20.4.1=20.3.2_928=20.3.2_929=20.4.1.0.1=20.3.2.1_930=19.2.4=20.5.0.1.1=20.4.1.1=20.3.3=19.2.4.0.1=20.3.2_937=20.3.3.1=20.5.1=20.1.3=20.3.3.0.4=20.3.3.1.2=20.3.3.1.1=20.4.1.2=20.3.3.0.2=20.4.1.1.5=20.4.1.0.01=20.4.1.0.02=20.3.3.1.7=20.3.3.1.5=20.5.1.0.1=20.3.3.1.10=20.3.3.0.8=20.4.2=20.4.2.0.1=20.3.4=20.3.3.0.14=19.2.4.0.8=19.2.4.0.9=20.3.4.0.1=20.3.2.0.5=20.6.1=20.5.1.0.2=20.3.3.0.17=20.6.1.1=20.6.0.18.3=20.3.2.0.6=20.6.0.18.4=20.4.2.0.2=20.3.3.0.16=20.3.4.0.5=20.6.1.0.1=20.3.4.0.6=20.6.2=20.7.1EFT2=20.3.4.0.9=20.3.4.0.11=20.4.2.0.4=20.3.3.0.18=20.7.1=20.6.2.1=20.3.4.1=20.5.1.1=20.4.2.1=20.4.2.1.1=20.3.4.1.1=20.3.813=20.3.4.0.19=20.4.2.2.1=20.5.1.2=20.3.4.2=20.3.814=20.4.2.2=20.6.2.2=20.3.4.2.1=20.7.1.1=20.3.4.1.2=20.6.2.2.2=20.3.4.0.20=20.6.2.2.3=20.4.2.2.2=20.3.5=20.6.2.0.4=20.4.2.2.3=20.3.4.0.24=20.6.2.2.7=20.6.3=20.3.4.2.2=20.4.2.2.4=20.7.1.0.2=20.8.1=20.3.5.0.8=20.3.5.0.9=20.4.2.2.8=20.3.5.0.7=20.6.3.0.7=20.6.3.0.5=20.6.3.0.10=20.6.3.0.2=20.7.2=20.9.1EFT2=20.6.3.0.11=20.6.3.1=20.6.3.0.14=20.6.4=20.9.1=20.6.3.0.19=20.6.3.0.18=20.3.6=20.9.1.1=20.6.3.0.23=20.6.4.0.4=20.6.3.0.25=20.6.5=20.6.3.0.27=20.9.2=20.9.2.1=20.6.3.0.29=20.6.3.0.31=20.6.3.0.32=20.10.1=20.6.3.0.33=20.9.2.0.01=20.9.1_LI_Images=20.10.1_LI_Images=20.9.2_LI_Images=20.3.7=20.9.3=20.6.5.1=20.11.1=20.11.1_LI_Images=20.6.3.1.1=20.9.3.0.2=20.6.5.1.2=20.9.3.0.3=20.4.2.3=20.6.3.2=20.6.4.1=20.6.3.0.38=20.6.3.0.39=20.3.5.1=20.3.4.3=20.9.3.1=20.3.3.2=20.6.5.2=20.3.7.1=20.10.1.1=20.6.5.2.1=20.3.4.0.25=20.6.2.2.4=20.6.1.2=20.11.1.1=20.9.3.0.5=20.3.4.0.26=20.6.5.1.3=20.6.3.0.40=20.1.3.1=20.9.2.2=20.6.5.2.3=20.6.5.1.4=20.6.5.3=20.6.3.0.41=20.9.3.0.7=20.6.5.1.5=20.9.3.0.4=20.6.4.0.19=20.6.5.1.6=20.9.3.0.8=20.6.3.3=20.3.7.2=20.6.5.4=20.6.5.1.7=20.9.3.0.12=20.6.4.2=20.6.5.5=20.9.3.2=20.11.1.2=20.6.3.4=20.10.1.2=20.6.5.1.9=20.9.3.0.16=20.6.3.0.45=20.6.5.1.10=20.9.3.0.17=20.6.5.2.4=20.6.4.0.21=20.9.3.0.18=20.6.3.0.46=20.6.3.0.47=20.9.2.3=20.9.3.2_LI_Images=20.9.3.0.21=20.9.3.0.20=20.9.4_LI_Images=20.9.4=20.6.5.1.11=20.12.1=20.12.1_LI_Images=20.6.5.1.13=20.9.3.0.23=20.6.5.2.8=20.9.4.1=20.9.4.1_LI_Images=20.9.3.0.25=20.9.3.0.24=20.6.5.1.14=20.3.8=20.6.6=20.9.3.0.26=20.6.3.0.51=20.9.3.0.29=20.12.2=20.12.2_LI_Images=20.6.6.0.1=20.13.1_LI_Images=20.9.4.0.4=20.13.1=20.9.4.1.1=20.9.5=20.9.5_LI_Images=20.12.3_LI_Images=20.12.3=20.9.4.1.3=20.6.7=20.9.5.1=20.9.5.1_LI_Images=20.9.4.1.6=20.14.1=20.14.1_LI_Images=20.9.5.2=20.9.5.2.1=20.9.5.2_LI_Images=20.12.3.1=20.12.4=20.15.1_LI_Images=20.15.1=20.9.5.1.4=20.9.5.2.7=20.9.5.2.13=20.9.6=20.9.6_LI_Images=20.9.5.2.14=20.6.8=20.12.4.0.03=20.16.1=20.16.1_LI_Images=20.12.4_LI_Images=20.9.5.2.16=20.12.4.0.4=20.12.401=20.9.5.3=20.9.5.3_LI_Images=20.12.4.1_LI_Images=20.12.4.1=20.9.5.2.21=20.9.6.0.3=20.12.4.0.6=20.15.2_LI_Images=20.15.2=20.12.4_Monthly_ES5=20.12.5=20.12.5_LI_Images=20.9.7=20.15.3=20.12.501=20.12.5.1_LI_Images=20.12.5.1=20.12.5.2_LI_Images=20.12.5.2=20.15.3.1=20.15.4_LI_Images=20.15.4=20.9.7.1=20.18.1=20.18.1_LI_Images=20.12.6_LI_Images=20.12.6=20.12.5.1.01=26.0.1=20.9.8=20.9.8_LI_Images=20.18.2=20.15.4.1_LI_Images=20.15.4.1=20.18.2_LI_Images=26.1.1=26.1.1_LI_Images=20.18.2.1_LI_Images=20.18.2.1=20.15.4.2_LI_Images=20.15.4.2=20.12.6.1=20.12.6.1_LI_Images=20.12.5.3=20.12.5.3_LI_Images=20.9.8.2_LI_Images=20.9.8.2=20.18.3=20.18.3_LI_Images=20.15.5=20.15.5_LI_Images=20.12.7=20.12.7_LI_Images=20.9.9=20.9.9_LI_Images=20.18.2.2=20.18.2.2_LI_Images=20.12.5.4=20.12.7.1_LI_Images=20.12.6.2_LI_Images=20.12.7.1=20.15.5.1=20.15.4.3=20.15.4.3_LI_Images=20.15.5.1_LI_Images=20.12.6.2=20.15.5.2=20.15.5.2_LI_Images=26.1.1.1_LI_Images=20.15.4.4=20.15.4.4_LI_Images=26.1.1.1=20.9.9.1_LI_Images=20.9.9.1=20.18.3.1_LI_Images=20.18.3.1=26.1.1.2=26.1.1.2_LI_Images=20.15.4.5=20.15.4.5_LI_Images=20.15.5.3=20.15.5.3_LI_Images=20.12.7.2_LI_Images=20.12.7.2=20.9.9.2=20.9.9.2_LI_Images=20.15.6=20.15.6_LI_Images

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 08/15/2026, 13:17:38 UTC

Technical Analysis

Cisco Catalyst SD-WAN Controller contains multiple improper input validation vulnerabilities grouped under CWE-20, identified as CVE-2026-20303. These issues were found during Cisco's internal security review and have been addressed in software hardening releases. The vulnerability allows an attacker to potentially compromise confidentiality, integrity, and availability of the affected system. The CVSS v3.1 base score is 9.9, with attack vector network, low attack complexity, requiring low privileges, no user interaction, and scope changed. The vulnerability affects many specific versions of Cisco Catalyst SD-WAN Controller as listed, but no official patch or remediation guidance is currently available.

Potential Impact

The vulnerability has a critical impact on affected Cisco Catalyst SD-WAN Controller versions, potentially allowing remote attackers to compromise confidentiality, integrity, and availability of the system. The CVSS score of 9.9 reflects the severity and ease of exploitation given network access and low complexity. No known exploits are currently reported in the wild.

Mitigation Recommendations

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Cisco has conducted internal reviews and released software hardening updates addressing these vulnerabilities, so users should monitor Cisco's official advisories for patches or updates. Until then, no specific mitigation steps are confirmed.

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Technical Details

Data Version
5.2
Assigner Short Name
cisco
Date Reserved
2025-10-08T11:59:15.408Z
Cvss Version
3.1
State
PUBLISHED

Threat ID: 6a736b62bf8831d5392da512

Added to database: 08/05/2026, 16:57:06 UTC

Last enriched: 08/15/2026, 13:17:38 UTC

Last updated: 09/19/2026, 17:25:44 UTC

Views: 62

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