CVE-2026-76504

CRITICAL

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 v3.1 Score

9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Published: 9/30/2026Modified: 10/3/2026

Related Intelligence (7)

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Cisco SD-WAN Manager hit by zero-day admin access attack

Cisco’s SD-WAN management software has been letting some attackers walk through an authentication check without having to prove who they are. The company says it has now fixed the flaw that was allowing it. The affected platform, Cisco Catalyst SD-WAN Manager , is used to configure and operate software-defined network deployments. Cisco said in an advisory that improper handling of URI encoding in

CVE-2026-76504
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CISA Adds Exploited Cisco Catalyst SD-WAN Manager Auth Bypass to KEV

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Wednesday added a critical authentication bypass flaw impacting Cisco Catalyst SD-WAN Manager to its Known Exploited Vulnerabilities (KEV), following reports of active exploitation. The vulnerability, tracked as CVE-2026-76504 (CVSS score: 9.8), could allow an unauthenticated, remote attacker to access an affected system with

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The Hacker News
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Cisco Warns of Attackers Exploiting Critical Authentication Bypass in SD-WAN Manager

Attackers are exploiting a critical flaw in Cisco Catalyst SD-WAN Manager, the system companies use to manage their Cisco SD-WAN networks, Cisco said in an advisory on September 30. The flaw, CVE-2026-76504, could allow a remote attacker with no login access to use the Manager's API as the admin user. Fixed releases are available, and there is no workaround. CVE-2026-76504 carries a

CVE-2026-76504
The Hacker News
CRITICALVulnerability

Critical Cisco Catalyst SD-WAN Manager API authentication bypass exploited in the wild (CVE-2026-76504)

Overview On September 30, 2026, Cisco published a security advisory for CVE-2026-76504 , a critical API authentication bypass vulnerability affecting Cisco Catalyst SD-WAN Manager. The vulnerability has a CVSSv3.1 score of 9.8 and results from improper handling of URL encoding ( CWE-177 ). An unauthenticated, remote attacker can send a crafted HTTP request that bypasses an authentication rule for

CVE-2026-76504CVE-2026-20127
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Cisco warns of new SD-WAN zero-day exploited in attacks

Cisco released security updates to address a critical zero-day in the Catalyst SD-WAN Manager (tracked as CVE-2026-76504) that attackers are actively exploiting to escalate to admin privileges. [...]

CVE-2026-76504
BleepingComputer
CRITICALVulnerability

NVD CRITICAL: CVE-2026-76504 — A vulnerability in the API session-based authentication management of Cisco Cata...

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 spe

CVE-2026-76504
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CISA KEV: Cisco Catalyst SD-WAN Manager — Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability

Cisco Catalyst SD-WAN Manager contains a hex encoding vulnerability that could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user due to improper handling of URI encoding in an HTTP request.

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CISA KEV

References (2)