Known exploited · Cisco
CVE-2026-76504: Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability
What it is
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.
- Vendor
- Cisco
- Product
- Catalyst SD-WAN Manager
- Added to KEV
- September 30, 2026
- CISA due date
- October 3, 2026
- Ransomware use
- Unknown
- Weakness
- CWE-177
What CISA requires
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.
Forensic triage
Yes
What to do now
- Find every instance of Catalyst SD-WAN Manager you run, including the forgotten ones, and check its version against the vendor advisory.
- Apply the vendor's fix or mitigation, before October 3, 2026 if you are bound by CISA's deadline, sooner if it faces the internet.
- Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
References
H2 Security
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Start freeSource: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.