diff --git a/polkadot/Cargo.lock b/polkadot/Cargo.lock
index eb5a58954c..79252bbe67 100644
--- a/polkadot/Cargo.lock
+++ b/polkadot/Cargo.lock
@@ -9398,9 +9398,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.74"
+version = "1.0.78"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee2bb9cd061c5865d345bb02ca49fcef1391741b672b54a0bf7b679badec3142"
+checksum = "d23c1ba4cf0efd44be32017709280b32d1cea5c3f1275c3b6d9e8bc54f758085"
 dependencies = [
  "itoa 1.0.1",
  "ryu",
diff --git a/polkadot/node/test/service/Cargo.toml b/polkadot/node/test/service/Cargo.toml
index 6e8afce0cc..ecd65f3f88 100644
--- a/polkadot/node/test/service/Cargo.toml
+++ b/polkadot/node/test/service/Cargo.toml
@@ -59,7 +59,7 @@ substrate-test-client = { git = "https://github.com/paritytech/substrate", branc
 
 [dev-dependencies]
 pallet-balances = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
-serde_json = "1.0.74"
+serde_json = "1.0.78"
 substrate-test-utils = { git = "https://github.com/paritytech/substrate", branch = "master" }
 tokio = { version = "1.15", features = ["macros"] }
 
diff --git a/polkadot/runtime/common/Cargo.toml b/polkadot/runtime/common/Cargo.toml
index 7e6815f18f..50c13f1725 100644
--- a/polkadot/runtime/common/Cargo.toml
+++ b/polkadot/runtime/common/Cargo.toml
@@ -58,7 +58,7 @@ pallet-babe = { git = "https://github.com/paritytech/substrate", branch = "maste
 pallet-treasury = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
 trie-db = "0.23.1"
-serde_json = "1.0.74"
+serde_json = "1.0.78"
 libsecp256k1 = "0.7.0"
 test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../primitives/test-helpers" }
 
diff --git a/polkadot/runtime/kusama/Cargo.toml b/polkadot/runtime/kusama/Cargo.toml
index 5b48c5de85..353142190a 100644
--- a/polkadot/runtime/kusama/Cargo.toml
+++ b/polkadot/runtime/kusama/Cargo.toml
@@ -98,7 +98,7 @@ tiny-keccak = "2.0.2"
 keyring = { package = "sp-keyring", git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-trie = { git = "https://github.com/paritytech/substrate", branch = "master" }
 separator = "0.4.1"
-serde_json = "1.0.74"
+serde_json = "1.0.78"
 
 [build-dependencies]
 substrate-wasm-builder = { git = "https://github.com/paritytech/substrate", branch = "master" }
diff --git a/polkadot/runtime/polkadot/Cargo.toml b/polkadot/runtime/polkadot/Cargo.toml
index b0f97da63e..52eb58cb06 100644
--- a/polkadot/runtime/polkadot/Cargo.toml
+++ b/polkadot/runtime/polkadot/Cargo.toml
@@ -94,7 +94,7 @@ tiny-keccak = "2.0.2"
 keyring = { package = "sp-keyring", git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-trie = { git = "https://github.com/paritytech/substrate", branch = "master" }
 trie-db = "0.23.1"
-serde_json = "1.0.74"
+serde_json = "1.0.78"
 separator = "0.4.1"
 
 [build-dependencies]
diff --git a/polkadot/runtime/test-runtime/Cargo.toml b/polkadot/runtime/test-runtime/Cargo.toml
index ab8880f415..4611388bf2 100644
--- a/polkadot/runtime/test-runtime/Cargo.toml
+++ b/polkadot/runtime/test-runtime/Cargo.toml
@@ -69,7 +69,7 @@ hex-literal = "0.3.4"
 tiny-keccak = "2.0.2"
 keyring = { package = "sp-keyring", git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-trie = { git = "https://github.com/paritytech/substrate", branch = "master" }
-serde_json = "1.0.74"
+serde_json = "1.0.78"
 
 [build-dependencies]
 substrate-wasm-builder = { git = "https://github.com/paritytech/substrate", branch = "master" }
diff --git a/polkadot/runtime/westend/Cargo.toml b/polkadot/runtime/westend/Cargo.toml
index 4ca3e3fa6d..3bd6a73b43 100644
--- a/polkadot/runtime/westend/Cargo.toml
+++ b/polkadot/runtime/westend/Cargo.toml
@@ -95,7 +95,7 @@ hex-literal = "0.3.4"
 tiny-keccak = "2.0.2"
 keyring = { package = "sp-keyring", git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-trie = { git = "https://github.com/paritytech/substrate", branch = "master" }
-serde_json = "1.0.74"
+serde_json = "1.0.78"
 
 [build-dependencies]
 substrate-wasm-builder = { git = "https://github.com/paritytech/substrate", branch = "master" }