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.