diff --git a/Cargo.toml b/Cargo.toml
index ceaf2be..c2feff2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,10 +10,10 @@ license-file = "LICENSE"
 [dependencies]
 libc = "0.2"
 anyhow = "1.0.56"
-protobuf = "3.2.0"
+protobuf = "= 3.2.0"
 
 [build-dependencies]
-protobuf-codegen = "3.2.0"
+protobuf-codegen = "= 3.2.0"
 
 [lib]
 name = "rust_criu"