diff --git a/npm/sarif-multitool-darwin/package.json b/npm/sarif-multitool-darwin/package.json
index 618e49dc5..da128a5d0 100644
--- a/npm/sarif-multitool-darwin/package.json
+++ b/npm/sarif-multitool-darwin/package.json
@@ -2,6 +2,9 @@
 	"name": "@microsoft/sarif-multitool-darwin",
 	"description": "SARIF Multitool for MacOS (Darwin)",
 	"version": "{version}",
+	"scripts": {
+		"postinstall": "chmod u+x Sarif.Multitool"
+	},
 	"author": "Microsoft",
 	"license": "MIT",
 	"repository": {
diff --git a/npm/sarif-multitool-linux/package.json b/npm/sarif-multitool-linux/package.json
index 7646e23b5..ad4243d20 100644
--- a/npm/sarif-multitool-linux/package.json
+++ b/npm/sarif-multitool-linux/package.json
@@ -2,6 +2,9 @@
 	"name": "@microsoft/sarif-multitool-linux",
 	"description": "SARIF Multitool for Linux",
 	"version": "{version}",
+	"scripts": {
+		"postinstall": "chmod u+x Sarif.Multitool"
+	},
 	"author": "Microsoft",
 	"license": "MIT",
 	"repository": {