Vulnerability · CVE-2026-76504
Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability
Published Sep 30, 2026 · catalog updated Oct 2, 2026 · Cisco Catalyst SD-WAN Manager
Patch now
CVE-2026-76504 is in the CISA known-exploited catalog, due Oct 3, 2026. Confirm Cisco Catalyst SD-WAN Manager against the vendor advisory and apply that fix. The CVSS score does not change the priority.
- Severity
- Critical9.8
- Known exploitation
- CISA KEV and VulnCheck KEV
- EPSS
- 1.82%
- Remediation
- Remediation guidance
- Affected products
- cpe cisco/catalyst sd-wan manager · vendor Cisco Catalyst SD-WAN Manager
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe cisco/catalyst sd-wan managerversion unspecified
- cpe cisco/catalyst sd-wan manager26.2
- vendor Cisco Catalyst SD-WAN Managerversion unspecified
How to fix CVE-2026-76504
Recommended remediation
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. CISA due date Oct 3, 2026.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
CVE-2026-76504 is in the CISA known-exploited catalog, due Oct 3, 2026. Confirm Cisco Catalyst SD-WAN Manager against the vendor advisory and apply that fix. The CVSS score does not change the priority.
Which versions are affected?
Compare what you have installed with cisco/catalyst sd-wan manager 26.2. 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.
What should an analyst verify?
CWE-177. EPSS 1.82%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Technology hubs
Code
The project this record applies to. Exploit listings stay in References.
No public source repository is identified for this product.
Timeline
Detection, updates, and resolution for this record.
Sep 30, 2026 · Catalog
Detected
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 specif
Sep 30, 2026 · CISA KEV
Known exploited
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
Oct 2, 2026 · Catalog
Updated
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 specif
Oct 3, 2026 · CISA KEV
Remediation due
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
Sources
- CISA KEVConfirmed exploitationCVE-2026-76504
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.
cisa.gov - Cisco Security AdvisoriesVendor advisoryCVE-2026-76504
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
sec.cloudapps.cisco.com - CVE.orgVulnerability recordCVE-2026-76504
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-76504
30-day exploitation probability 1.8%
first.org - NIST NVDVulnerability recordCVE-2026-76504
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
nvd.nist.gov - Rapid7 Vulnerability DatabaseResearchCVE-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
rapid7.com - VulnCheck KEVConfirmed exploitationCVE-2026-76504
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.
vulncheck.com
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.