GNU GRUB (aka GRUB2) through 2.12 does not use a constant-time algorithm for grub_crypto_memcmp and thus allows side-channel attacks.
Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Grub2 | Ubuntu | esm-infra-legacy/trusty | * |
| Grub2-signed | Ubuntu | esm-infra-legacy/trusty | * |