diff --git a/Cargo.lock b/Cargo.lock
index 67e8ebbd..74fdbaa3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -202,7 +202,7 @@ version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 dependencies = [
- "hermit-abi",
+ "hermit-abi 0.1.19",
  "libc",
  "winapi",
 ]
@@ -1737,6 +1737,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "hermit-abi"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee512640fe35acbfb4bb779db6f0d80704c2cacfa2e39b601ef3e3f47d1ae4c7"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "hex"
 version = "0.4.3"
@@ -2527,11 +2536,11 @@ dependencies = [
 
 [[package]]
 name = "num_cpus"
-version = "1.14.0"
+version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6058e64324c71e02bc2b150e4f3bc8286db6c83092132ffa3f6b1eab0f9def5"
+checksum = "0fac9e2da13b5eb447a6ce3d392f23a29d8694bff781bf03a16cd9ac8697593b"
 dependencies = [
- "hermit-abi",
+ "hermit-abi 0.2.6",
  "libc",
 ]
 
diff --git a/zebra-rpc/Cargo.toml b/zebra-rpc/Cargo.toml
index 6f5cdfab..ea637cc7 100644
--- a/zebra-rpc/Cargo.toml
+++ b/zebra-rpc/Cargo.toml
@@ -40,7 +40,7 @@ hyper = { version = "0.14.23", features = ["http1", "server"] }
 jsonrpc-core = "18.0.0"
 jsonrpc-derive = "18.0.0"
 jsonrpc-http-server = "18.0.0"
-num_cpus = "1.14.0"
+num_cpus = "1.15.0"
 
 # zebra-rpc needs the preserve_order feature in serde_json, which is a dependency of jsonrpc-core
 serde_json = { version = "1.0.91", features = ["preserve_order"] }