diff --git a/src/rust/crypto/Cargo.toml b/src/rust/crypto/Cargo.toml
index 5f752abe0..b97a241f9 100644
--- a/src/rust/crypto/Cargo.toml
+++ b/src/rust/crypto/Cargo.toml
@@ -11,7 +11,7 @@ name = "crypto"
 path = "lib.rs"
 
 [dependencies]
-libc = "=0.2.138"
+libc = "=0.2.156"
 digest = "=0.10.6"
 rand_core = { version = "=0.6.4", default-features = false }
 
diff --git a/src/rust/external/Cargo.toml b/src/rust/external/Cargo.toml
index 4f6fc3e92..f0233fc90 100644
--- a/src/rust/external/Cargo.toml
+++ b/src/rust/external/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.0.1"
 name = "external"
 
 [dependencies]
-libc = "=0.2.138"
+libc = "=0.2.156"
 smartlist = { path = "../smartlist" }
 tor_allocate = { path = "../tor_allocate" }
 
diff --git a/src/rust/protover/Cargo.toml b/src/rust/protover/Cargo.toml
index ad874e1f5..6e2eb18cc 100644
--- a/src/rust/protover/Cargo.toml
+++ b/src/rust/protover/Cargo.toml
@@ -11,7 +11,7 @@ name = "protover"
 test_linking_hack = []
 
 [dependencies]
-libc = "=0.2.138"
+libc = "=0.2.156"
 
 [dependencies.smartlist]
 path = "../smartlist"
diff --git a/src/rust/tor_allocate/Cargo.toml b/src/rust/tor_allocate/Cargo.toml
index 4660d0f61..11cb79342 100644
--- a/src/rust/tor_allocate/Cargo.toml
+++ b/src/rust/tor_allocate/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.0.1"
 name = "tor_allocate"
 
 [dependencies]
-libc = "=0.2.138"
+libc = "=0.2.156"
 
 [lib]
 name = "tor_allocate"
diff --git a/src/rust/tor_util/Cargo.toml b/src/rust/tor_util/Cargo.toml
index d048e2374..37b7022b4 100644
--- a/src/rust/tor_util/Cargo.toml
+++ b/src/rust/tor_util/Cargo.toml
@@ -14,7 +14,7 @@ path = "../tor_allocate"
 path = "../tor_log"
 
 [dependencies]
-libc = "=0.2.138"
+libc = "=0.2.156"
 
 [features]
 # We have to define a feature here because doctests don't get cfg(test),