KEV catalog · CISA Known Exploited Vulnerabilities
CVE-2026-76504
9.8
Details
Descriptions
KEV: 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.
NVD: 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.
Compliance SSVC + BOD 26-04
Research metadata
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU/csaf/cisco-sa-sdwan-webauth-xr8beuuU.json
https://nvd.nist.gov/vuln/detail/CVE-2026-76504
https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json
https://github.com/ShadowForge-Cyber/CVE-2026-76504-Proof-of-concept
QC notes
Hunting hypothesis agent
Hunt serviceproxy-access.log for POST /%6a_security_check requests to Catalyst SD-WAN Manager from unknown IPs and vmanage-server.log for j_security_check entries with viptela-reserved- users showing hex-encoding auth bypass.
Research details
Tia coverage
When Tia's reporting first covered this CVE and whether a report claimed exploitation before the KEV listing. Lead-time deltas are measured from the exploitation report only — plain coverage is not exploitation intel. See the story links under Mentioned in for coverage detail.
Mentioned in
cisco-sd-wan-manager-auth-bypass-cve-2026-76504-cvss-9-8-under-e
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