From c966193b981f84d4d6894936dcbb47b363d59456 Mon Sep 17 00:00:00 2001
From: Srinjoy Dev <srinjoydev1104@gmail.com>
Date: Tue, 21 Oct 2025 16:49:31 +0000
Subject: [PATCH] fix: prevent crash when BigInt passed to res.status()

Replace JSON.stringify() with String() in error messages to prevent
uncaught TypeError when non-JSON-serializable values (like BigInt)
are passed to res.status() or res.sendStatus().

The error messages now include both the stringified value and its type
for better debugging, e.g., 'Invalid status code: 200 (bigint)'.

This change maintains backward compatibility while making the library
more robust against edge cases that could crash the server.

Fixes #6756
---
 lib/response.js        |  4 ++--
 test/res.sendStatus.js | 36 ++++++++++++++++++++++++++++++++++++
 test/res.status.js     | 12 ++++++++++++
 3 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/lib/response.js b/lib/response.js
index 7a2f0ecce56..1095ce4e864 100644
--- a/lib/response.js
+++ b/lib/response.js
@@ -64,11 +64,11 @@ module.exports = res
 res.status = function status(code) {
   // Check if the status code is not an integer
   if (!Number.isInteger(code)) {
-    throw new TypeError(`Invalid status code: ${JSON.stringify(code)}. Status code must be an integer.`);
+    throw new TypeError(`Invalid status code: ${String(code)} (${typeof code}). Status code must be an integer.`);
   }
   // Check if the status code is outside of Node's valid range
   if (code < 100 || code > 999) {
-    throw new RangeError(`Invalid status code: ${JSON.stringify(code)}. Status code must be greater than 99 and less than 1000.`);
+    throw new RangeError(`Invalid status code: ${String(code)} (${typeof code}). Status code must be greater than 99 and less than 1000.`);
   }
 
   this.statusCode = code;
diff --git a/test/res.sendStatus.js b/test/res.sendStatus.js
index b244cf9d173..e710dafb0aa 100644
--- a/test/res.sendStatus.js
+++ b/test/res.sendStatus.js
@@ -40,5 +40,41 @@ describe('res', function () {
         .get('/')
         .expect(500, /TypeError: Invalid status code/, done)
     })
+
+    it('should raise error for BigInt status code', function (done) {
+      var app = express()
+
+      app.use(function (req, res) {
+        res.sendStatus(200n)
+      })
+
+      request(app)
+        .get('/')
+        .expect(500, /TypeError: Invalid status code: 200 \(bigint\)/, done)
+    })
+
+    it('should raise error for string status code', function (done) {
+      var app = express()
+
+      app.use(function (req, res) {
+        res.sendStatus('200')
+      })
+
+      request(app)
+        .get('/')
+        .expect(500, /TypeError: Invalid status code: 200 \(string\)/, done)
+    })
+
+    it('should raise error for object status code', function (done) {
+      var app = express()
+
+      app.use(function (req, res) {
+        res.sendStatus({ status: 200 })
+      })
+
+      request(app)
+        .get('/')
+        .expect(500, /TypeError: Invalid status code.*\(object\)/, done)
+    })
   })
 })
diff --git a/test/res.status.js b/test/res.status.js
index 59c8a57e702..8c50f894612 100644
--- a/test/res.status.js
+++ b/test/res.status.js
@@ -200,6 +200,18 @@ describe('res', function () {
           .get('/')
           .expect(500, /Invalid status code/, done);
       });
+
+      it('should raise error for BigInt status code', function (done) {
+        var app = express();
+
+        app.use(function (req, res) {
+          res.status(200n).end();
+        });
+
+        request(app)
+          .get('/')
+          .expect(500, /TypeError: Invalid status code: 200 \(bigint\)/, done);
+      });
     });
   });
 });