CVE-2026-76413 Cisco CVE debrief

Who should care

Cisco ASDM administrators and security teams responsible for managing and securing Cisco Adaptive Security Device Manager (ASDM) and Cisco Secure FMC Software should assess exposure and prioritize patching or mitigation to prevent potential unauthorized access and disruption of legitimate administrator access.

Why it matters

CVE-2026-76413 is a high-severity vulnerability in Cisco Adaptive Security Device Manager (ASDM) single sign-on (SSO) handler for Cisco Secure FMC Software, allowing unauthenticated remote attackers to log in as the administrator user. Cisco ASDM administrators and security teams should assess exposure and prioritize patching or mitigation to prevent potential unauthorized access and disruption of legitimate administrator access.

• Potential unauthorized access to Cisco ASDM
• Possible disruption of legitimate administrator access
• Need for verification of Cisco ASDM configurations and patch application

Technical summary

A vulnerability in Cisco Adaptive Security Device Manager (ASDM) single sign-on (SSO) handler for Cisco Secure FMC Software could allow an unauthenticated, remote attacker to log in as the Cisco ASDM administrator user. The vulnerability is due to improper management of the Cisco ASDM SSO token. An attacker could exploit this vulnerability by performing session token forgery techniques. A successful exploit could allow the attacker to log in as the administrator user and, by repeating this action, keep legitimate administrators locked out of the ASDM indefinitely.

Defensive priority

High priority for Cisco ASDM administrators and security teams

Recommended defensive actions

• Review and update Cisco ASDM configurations to prevent unauthorized access
• Implement additional security measures to monitor and detect suspicious activity
• Verify and apply any available patches or updates from Cisco
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and NVD entry provide details on the vulnerability in Cisco Adaptive Security Device Manager (ASDM) single sign-on (SSO) handler for Cisco Secure FMC Software. Evidence is limited to public sources and may not reflect the full scope or impact of the vulnerability. Defenders should verify affected systems and apply patches or mitigations according to vendor guidance.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.