diff --git a/packages/kernel-wasmtime/package.json b/packages/kernel-wasmtime/package.json
index 9080fb47..068398bf 100644
--- a/packages/kernel-wasmtime/package.json
+++ b/packages/kernel-wasmtime/package.json
@@ -24,7 +24,7 @@
   },
   "devDependencies": {
     "@types/node": "^26.1.1",
-    "fast-check": "^3.22.0",
+    "fast-check": "^4.9.0",
     "typescript": "^5.7.0"
   },
   "engines": {
diff --git a/packages/mcp-firewall/package.json b/packages/mcp-firewall/package.json
index 8c2d0588..4ee7e6a5 100644
--- a/packages/mcp-firewall/package.json
+++ b/packages/mcp-firewall/package.json
@@ -22,7 +22,7 @@
   },
   "devDependencies": {
     "@types/node": "^26.1.1",
-    "fast-check": "^3.22.0",
+    "fast-check": "^4.9.0",
     "typescript": "^5.7.0",
     "zod": "^3.22.0"
   },