CVE-2021-3521

There is a flaw in RPM’s signature functionality. OpenPGP subkeys are associated with a primary key via a “binding signature.”[1] RPM does not check the binding signature of subkeys prior to importing them. If an attacker is able to add or socially engineer another party to add a malicious subkey to a legitimate public key, RPM could wrongly trust a malicious signature. The greatest impact of this flaw is to data integrity. 1. https://tools.ietf.org/html/rfc4880#section-5.2.1