diff --git a/tools/cargo-deny/deny.toml b/tools/cargo-deny/deny.toml
index 62a6d7d5bcd..be28a0684ff 100644
--- a/tools/cargo-deny/deny.toml
+++ b/tools/cargo-deny/deny.toml
@@ -14,6 +14,7 @@ allow = [
   "ISC",
   "BlueOak-1.0.0",
   "BSL-1.0",
+  "Zlib",
 ]
 exceptions = [
   { allow = ["LicenseRef-Ring-ISC-OpenSSL"], name = "ring", version = "*" },