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CVE-2026-76504criticalunder attackCWE-177

Cisco Catalyst SD-WAN Manager System Account Authorization Bypass Vulnerability

75Vexday Risk Score

Prioritize patching. It under exploitation confirmed by CISA and has a public proof of concept.

ssvc Actcvss 9.8
from disclosure to weapon0 days
Published on NVDSep 30
1st PoCSep 30
CISA KEVSep 30
exploitation probability
—
observed exploitation
yesCISA + VulnCheck
1 public exploit(s)
Action required by CISAfederal deadline: 2026-10-03

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.

In short

A flaw in Cisco Catalyst SD-WAN Manager allows attackers to bypass login checks by crafting special HTTP requests, gaining admin access without credentials.

Technical detail

The vulnerability stems from improper URI encoding handling in API session authentication that fails to properly restrict access to protected endpoints. An unauthenticated remote attacker can send a crafted HTTP request that bypasses authentication rules and obtains admin-level API access. Exploitation requires network access to the affected system's API endpoint but no prior credentials.

Summary generated and translated by AI from the official 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
Cisco · Cisco Catalyst SD-WAN Manager
public PoCs found — 1
githubgithub.com/ShadowForge-Cyber/CVE-2026-76504-Proof-of-concept★ 0
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
References
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuUhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-76504