Amazon Linux AMI Security Advisory: ALAS-2018-1025
Advisory Release Date: 2018-05-25 18:21 Pacific
Unenforced configuration allows for apparently valid certifications actually signed by signing subkeys
GnuPG 2.2.4 and 2.2.5 does not enforce a configuration in which key certification requires an offline master Certify key, which results in apparently valid certifications that occurred only with access to a signing subkey. (CVE-2018-9234 )
Run yum update gnupg2 to update your system.