CVE-2026-76504 — Catalyst Sd-Wan Manager
CRITICALCVE-2026-76504 is a critical-severity (CVSS 9.8) CWE-177 vulnerability in cisco catalyst sd-wan manager. It is in CISA's Known Exploited Vulnerabilities catalog (added 2026-09-30) — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.
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…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2026-09-30. Federal agencies were required to remediate by 2026-10-03.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2026-76504.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-76504 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 383,485 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
Affected Products
catalyst sd-wan managerciscoDetection & mitigation playbook
Vendor / applianceDetect
Inventory every cisco catalyst sd-wan manager deployment and check each version against the affected-products list above.
Fix
Apply the cisco catalyst sd-wan manager security patch or hotfix for CVE-2026-76504 on the affected version, following the vendor advisory for your exact build.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2026-76504 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.