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.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Gnupg | Gnupg | 2.2.4 (including) | 2.2.4 (including) |
| Gnupg | Gnupg | 2.2.5 (including) | 2.2.5 (including) |
| Gnupg | Ubuntu | upstream | * |
| Gnupg2 | Ubuntu | bionic | * |
| Gnupg2 | Ubuntu | devel | * |
| Gnupg2 | Ubuntu | esm-infra/bionic | * |
| Gnupg2 | Ubuntu | upstream | * |