Cisco Asa Certificate Validation Failed. Ee Key Is Too Small [new] Jun 2026

Additionally, many organizations migrated their internal CA to issue 2048-bit certificates years ago, but legacy devices (old routers, printers, or forgotten VPN clients) retained their old 1024-bit certificates. The moment the ASA reboots or a tunnel renegotiates, the validation fails.

The error occurs when the End-Entity (EE) certificate—typically the identity certificate used for ASDM management or VPN connections—uses an RSA key size that does not meet the minimum security requirements of the Cisco ASA software or its underlying cryptographic policy. Understanding the Error

On the peer firewall/router, check its identity certificate. If it’s not a Cisco device, use its equivalent command or ask the remote admin to provide the certificate details. cisco asa certificate validation failed. ee key is too small

crypto ca trustpoint NEW_TP keypair NEW_2048_KEY subject-name CN=://yourdomain.com enrollment terminal Use code with caution. Copied to clipboard

Let me clarify: On a Cisco ASA, when acting as an SSL/TLS server (e.g., for VPN), it validates client certificates if client cert auth is enabled. The error “EE key is too small” means a client presented a certificate whose public key size was below the ASA’s configured minimum (default often 1024 or 2048 depending on version/configuration). But in their case, no client cert auth was enabled. Understanding the Error On the peer firewall/router, check

You are most likely to see this error in three specific deployment scenarios:

Generate the request ( crypto ca enroll NEW_TP ), send it to your CA, and then import the signed certificate. Copied to clipboard Let me clarify: On a

Few things disrupt a production network as abruptly as a VPN tunnel dropping or failing to establish. When working with Cisco Adaptive Security Appliances (ASA) and Firepower Threat Defense (FTD), one of the most cryptic and frustrating error messages you can encounter in the logs is: