diff --git a/Cargo.lock b/Cargo.lock
index 1e2d1c4e665..15632a9b00a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3205,6 +3205,6 @@ dependencies = [
 
 [[package]]
 name = "zlib-rs"
-version = "0.2.1"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e942bb8453553ee59b701f977d5331a512f8dd07906153bbe050cb9bb58a4811"
+checksum = "2ca4a9dc6566c9224cc161dedc5577bd81f4a9ee0f9fbe80592756d096b07ee5"
diff --git a/rustls/Cargo.toml b/rustls/Cargo.toml
index 38c5463445d..0717aceedaf 100644
--- a/rustls/Cargo.toml
+++ b/rustls/Cargo.toml
@@ -29,7 +29,7 @@ subtle = { version = "2.5.0", default-features = false }
 webpki = { package = "rustls-webpki", version = "0.102.6", features = ["alloc"], default-features = false }
 pki-types = { package = "rustls-pki-types", version = "1.7", features = ["alloc"] }
 zeroize = "1.7"
-zlib-rs = { version = "0.2", optional = true }
+zlib-rs = { version = "0.4", optional = true }
 
 [features]
 default = ["aws_lc_rs", "logging", "std", "tls12"]