Vault and Vault Enterprise (“Vault”) TLS certificate auth method did not correctly validate client certificates when configured with a non-CA certificate as [+trusted certificate+|https://developer.hashicorp.com/vault/api-docs/auth/cert#certificate]. In this configuration, an attacker may be able to craft a malicious certificate that could be used to impersonate another user. Fixed in Vault Community Edition 1.20.1 and Vault Enterprise 1.20.1, 1.19.7, 1.18.12, and 1.16.23.
The product does not validate, or incorrectly validates, a certificate.