diff --git a/cpufeatures/Cargo.toml b/cpufeatures/Cargo.toml
index 94f8ace1..244ac4a2 100644
--- a/cpufeatures/Cargo.toml
+++ b/cpufeatures/Cargo.toml
@@ -15,7 +15,7 @@ edition = "2018"
 readme = "README.md"
 
 [target.aarch64-apple-darwin.dependencies]
-libc = "0.2.103"
+libc = "0.2.68"
 
 [target.'cfg(all(target_arch = "aarch64", target_os = "linux"))'.dependencies]
-libc = "0.2.103"
+libc = "0.2.68"
diff --git a/wycheproof2blb/Cargo.toml b/wycheproof2blb/Cargo.toml
index 2300ba7a..5bd025b3 100644
--- a/wycheproof2blb/Cargo.toml
+++ b/wycheproof2blb/Cargo.toml
@@ -12,5 +12,5 @@ edition = "2018"
 [dependencies]
 blobby = { version = "0.3.1", path = "../blobby" }
 hex = "0.4"
-serde = { version = "1", features = ["derive"] }
+serde = { version = "1.0.103", features = ["derive"] }
 serde_json = "1"
diff --git a/zeroize/derive/Cargo.toml b/zeroize/derive/Cargo.toml
index fac9ed08..bad02b70 100644
--- a/zeroize/derive/Cargo.toml
+++ b/zeroize/derive/Cargo.toml
@@ -17,7 +17,7 @@ proc-macro = true
 proc-macro2 = "1"
 quote = "1"
 syn = "1"
-synstructure = "0.12"
+synstructure = "0.12.2"
 
 [package.metadata.docs.rs]
 rustdoc-args = ["--document-private-items"]