diff --git a/lightning/Cargo.toml b/lightning/Cargo.toml
index e98756d552f..d005dd6889a 100644
--- a/lightning/Cargo.toml
+++ b/lightning/Cargo.toml
@@ -46,7 +46,7 @@ hex = { version = "0.4", optional = true }
 regex = { version = "1.5.6", optional = true }
 backtrace = { version = "0.3", optional = true }
 
-core2 = { version = "0.3.0", optional = true, default-features = false }
+core2 = { version = "0.4.0", optional = true, default-features = false }
 
 [dev-dependencies]
 hex = "0.4"