Cisco Catalyst SD-WAN Manager System Account Authorization Bypass Vulnerability
Summary
| CVE | CVE-2026-76504 |
|---|---|
| State | PUBLISHED |
| Assigner | cisco |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-30 13:17:20 UTC |
| Updated | 2026-10-01 04:18:19 UTC |
| Description | A vulnerability in the API session-based authentication management of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user. This vulnerability is due to improper handling of URI encoding in an HTTP request, which allows the request to bypass an authentication rule that is intended to restrict access to a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted HTTP request to the API of the affected system. A successful exploit could allow the attacker to bypass authentication and gain access to the API as the admin user. |
Risk And Classification
Primary CVSS: v3.1 9.8 CRITICAL from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA KEV: Listed on 2026-09-30; due 2026-10-03; ransomware use Unknown
Problem Types: CWE-177 | CWE-177 Improper Handling of URL Encoding (Hex Encoding)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | CVSSV3_1 | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA Known Exploited Vulnerability
| Vendor | Cisco |
|---|---|
| Product | Catalyst SD-WAN Manager |
| Name | Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability |
| Required Action | Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. |
| Notes | https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU ; ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-76504 |
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Cisco | Catalyst Sd-wan Manager | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.6 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.7 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.8 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 17.2.10 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.6.1 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.2.0 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.4.3 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.4.1 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 17.2.8 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.3.1 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.4.0 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.1 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 17.2.6 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 17.2.9 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.4 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 17.2.5 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.1.1 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.5 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.4.0.1 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.3 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 17.2.7 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 17.2.4 | Not specified |
| CNA | Cisco | Cisco Catalyst SD-WAN Manager | affected 18.3.0 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-... | [email protected] | sec.cloudapps.cisco.com | Mitigation, Vendor Advisory |
| www.cisa.gov/known-exploited-vulnerabilities-catalog | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | www.cisa.gov | US Government Resource |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
| CISA Known Exploited Vulnerabilities catalog | CISA | www.cisa.gov | kev |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-09-30T00:00:00.000Z | CVE-2026-76504 added to CISA KEV |
Exploits
CNA: In September 2026, the Cisco PSIRT became aware of active exploitation of this vulnerability. Cisco strongly recommends that customers upgrade to a fixed software release to remediate this vulnerability.
There are currently no legacy QID mappings associated with this CVE.