diff --git a/deny.toml b/deny.toml
index d62f5a4..8552094 100644
--- a/deny.toml
+++ b/deny.toml
@@ -179,7 +179,7 @@ registries = [
 # https://embarkstudios.github.io/cargo-deny/checks/bans/cfg.html
 [bans]
 # Lint level for when multiple versions of the same crate are detected
-multiple-versions = "warn"
+multiple-versions = "deny"
 # Lint level for when a crate version requirement is `*`
 wildcards = "allow"
 # The graph highlighting used when creating dotgraphs for crates