diff --git a/deny.toml b/deny.toml
index 2278d2ddde4..0352fcfaecf 100644
--- a/deny.toml
+++ b/deny.toml
@@ -23,6 +23,7 @@ allow = [
     "Unicode-DFS-2016",
     "Unlicense",
     "MPL-2.0",
+    "Zlib",
     # https://github.com/briansmith/ring/issues/902
     "LicenseRef-ring",
 ]