CVE-2026-20107
📋 TL;DR
This vulnerability allows authenticated local attackers with CLI access to cause Cisco APIC devices to unexpectedly reload by issuing crafted commands, resulting in denial of service. It affects Cisco Application Policy Infrastructure Controller systems where users have CLI access. The vulnerability stems from insufficient input validation in the Object Model CLI component.
💻 Affected Systems
- Cisco Application Policy Infrastructure Controller (APIC)
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption as the APIC controller reloads, potentially affecting all managed network devices and causing extended downtime.
Likely Case
Temporary service interruption during controller reload, disrupting network management and policy enforcement until system restores.
If Mitigated
Minimal impact if proper access controls limit CLI access to trusted administrators only.
🎯 Exploit Status
Exploitation requires authenticated CLI access and knowledge of specific crafted commands.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco Security Advisory for specific fixed versions
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apic-dos-rNus8EFw
Restart Required: Yes
Instructions:
1. Review Cisco Security Advisory for affected versions. 2. Download and apply the appropriate patch from Cisco. 3. Restart the APIC controller as required. 4. Verify the fix using version check commands.
🔧 Temporary Workarounds
Restrict CLI Access
allLimit CLI access to only essential, trusted administrators to reduce attack surface.
# Configure role-based access control to restrict CLI privileges
# Example: apic1(config)# role name restricted no feature cli
Monitor CLI Activity
allImplement enhanced logging and monitoring of CLI commands to detect exploitation attempts.
# Enable detailed CLI command logging
# Example: apic1(config)# logging monitor 7
🧯 If You Can't Patch
- Implement strict role-based access control to limit CLI access to minimum necessary personnel only.
- Deploy network segmentation to isolate APIC controllers from general user networks.
🔍 How to Verify
Check if Vulnerable:
Check APIC version against Cisco Security Advisory; systems running vulnerable versions with CLI access enabled are at risk.Check Version:
show versionVerify Fix Applied:
Verify APIC version matches patched version from Cisco advisory and test that crafted CLI commands no longer cause reloads.📡 Detection & Monitoring
Log Indicators:
- Unexpected APIC reload events
- Multiple failed CLI command attempts
- Suspicious CLI command patterns from non-admin users
Network Indicators:
- Sudden loss of connectivity to APIC management interface
- APIC service disruption alerts
SIEM Query:
source="apic" AND (event_type="reload" OR command="*crafted*" OR user="*cli*" AND result="failure")