The security of a TLS connection heavily depends on the used keysize. If the size of the used key is too small, it becomes easy for an attacker to break the encryption.
Security Assessment

CVSS Vector: AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Vulnerability Information
The security of a TLS connection heavily depends on the used keysize. If the size of the used key is too small, it becomes easy for an attacker to break the encryption.
Guides
To get a certificate with a larger keysize, you need to generate a new key. To generate a secure key and a new certificate, follow the instructions in: Configure Trusted Certificates.