diff --git a/Cargo.lock b/Cargo.lock
index 7b570fcb1..ad2db9dd2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -145,7 +145,22 @@ dependencies = [
  "cpufeatures 0.2.17",
  "curve25519-dalek-derive",
  "digest",
- "fiat-crypto",
+ "fiat-crypto 0.2.9",
+ "rustc_version",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "curve25519-dalek"
+version = "5.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5eed333089e2e1c1ac8c6c0398e5e2497b4c9926ca6d0365ed1e099afa5bc23"
+dependencies = [
+ "cfg-if",
+ "cpufeatures 0.3.0",
+ "curve25519-dalek-derive",
+ "fiat-crypto 0.3.0",
  "rustc_version",
  "subtle",
  "zeroize",
@@ -239,7 +254,7 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "70e796c081cee67dc755e1a36a0a172b897fab85fc3f6bc48307991f64e4eca9"
 dependencies = [
- "curve25519-dalek",
+ "curve25519-dalek 4.1.3",
  "ed25519",
  "serde",
  "sha2",
@@ -253,6 +268,12 @@ version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "28dea519a9695b9977216879a3ebfddf92f1c08c05d984f8996aecd6ecdc811d"
 
+[[package]]
+name = "fiat-crypto"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "64cd1e32ddd350061ae6edb1b082d7c54915b5c672c389143b9a63403a109f24"
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.9"
@@ -379,7 +400,7 @@ dependencies = [
  "bitvec",
  "blake3",
  "cc",
- "curve25519-dalek",
+ "curve25519-dalek 5.0.0",
  "ed25519-dalek",
  "glob",
  "heapless",
@@ -683,7 +704,7 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c7e468321c81fb07fa7f4c636c3972b9100f0346e5b6a9f2bd0603a52f7ed277"
 dependencies = [
- "curve25519-dalek",
+ "curve25519-dalek 4.1.3",
  "rand_core",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index be62fb7a3..b87a7ab08 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -868,7 +868,7 @@ heapless = { version = "0.8",  default-features = false }
 
 # External crypto (optional; in-tree implementations are the default).
 ed25519-dalek    = { version = "2.1.1", default-features = false, features = ["alloc", "zeroize"], optional = true }
-curve25519-dalek = { version = "4.1.3", default-features = false, features = ["alloc", "zeroize"], optional = true }
+curve25519-dalek = { version = "5.0.0", default-features = false, features = ["alloc", "zeroize"], optional = true }
 x25519-dalek     = { version = "2",     default-features = false, features = ["static_secrets"], optional = true }
 sha3             = { version = "0.10",  default-features = false, optional = true }