Critical severity · published Sep 30, 2026
CVE-2026-76504
Cisco Catalyst SD-WAN Manager System Account Authorization Bypass Vulnerability
In wildKEV
9.8
CVSS
38.9%
EPSS
Yes
On KEV
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 vector
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
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)38.9% · higher than 99% of CVEs
Exploited in the wildYes
CISA KEVListed Sep 30, 2026
Federal remediation dueOct 3, 2026
Ransomware campaign useNot known
Affected products
Which versions
CC
Cisco Catalyst SD-WAN Manager · Cisco
20.1.12; 19.2.1; 18.4.4; 18.4.5; 20.1.1.1; 20.1.1; +34 more · source: vendor
CS
Catalyst Sd-wan Manager · Cisco
before 20.9.10.1; 20.12 before 20.12.8.2; 20.15 before 20.15.6.1; 20.18 before 20.18.4.1; 26.1 before 26.1.2.1; 26.2 · source: NVD, KEV
In the news
VulnerabilityCritical
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
Oct 1, 2026·The Hacker News
VulnerabilityHigh
New Cisco SD-WAN zero-day exploited in-the-wild (CVE-2026-76504)
For the fifth time this year, Cisco revealed attackers have exploited a vulnerability (CVE-2026-76504) in its SD-WAN solution in zero-day attacks. The vendor’s incident responders became aware of active exploitation of this vulnerability in September 2026, after getting pinged and resolving a Cisco Technical Assistance Center (TAC) support case. Cisco has yet to share any details about the attacks, but it has provided indicators of compromise defenders should look for to check whether they have … More → The post New Cisco SD-WAN zero-day exploited in-the-wild (CVE-2026-76504) appeared first on Help Net Security .
Oct 1, 2026·Help Net Security
VulnerabilityCritical
U.S. CISA adds Cisco Catalyst SD-WAN Manager flaw to its Known Exploited Vulnerabilities catalog
U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds Cisco Catalyst SD-WAN Manager flaw to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added a Cisco Catalyst SD-WAN Manager flaw, tracked as CVE-2026-76504 (CVSS score of 9.8), to its Known Exploited Vulnerabilities (KEV) catalog. The vulnerability resides in Cisco Catalyst SD-WAN Manager’s […]
Oct 1, 2026·Security Affairs
VulnerabilityCritical
Cisco Warns of Attackers Exploiting Critical Authentication Bypass in SD-WAN Manager
Attackers are exploiting a new critical zero-day 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. It carries a
Sep 30, 2026·The Hacker News
VulnerabilityHigh
CISA Adds One Known Exploited Vulnerability to Catalog  
CISA has added one new vulnerability to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation. CVE-2026-76504 Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability This type of vulnerability is a frequent attack vector for malicious cyber actors and poses significant risks to the federal enterprise.  Binding Operational Directive (BOD) 26-04: Prioritizing Security Updates Based on Risk establishes vulnerability management requirements for Federal Civilian Executive Branch (FCEB) agencies. BOD 26-04 reinforces the importance of the KEV Catalog and requires federal agencies to prioritize rapid remediation of high-risk vulnerabilities, specifically those identified by Common Vulnerabilities and Exposures (CVEs) listed in CISA’s KEV Catalog on publicly exposed assets that grant total control of the asset post-exploitation, while deferring action for lower-risk vulnerabilities. BOD 26-04 further establishes basic expectations for when agencies must check whether threat actors compromised the system before the patch was applied.  While BOD 26-04 applies only to FCEB agencies, CISA encourages all organizations to adopt risk-based vulnerability management and prioritize remediation of KEV Catalog vulnerabilities . CISA will continue to add vulnerabilities to the catalog that meet the specified criteria .  Aware of an exploited vulnerability not currently listed in the KEV Catalog? Submit it for potential ad...
Sep 30, 2026·US-CERT Current Activity
VulnerabilityCritical
[CISA KEV] CVE-2026-76504: 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.
CSCatalyst SD-WAN ManagerCVE-2026-76504
Sep 30, 2026·CISA KEV
Affected product
CC
Cisco Catalyst SD-WAN Manager
Cisco
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