From c95ebdf15328e3a3be886d1844c6be437172ccb2 Mon Sep 17 00:00:00 2001
From: abhijeet117 <abhijeetkumarsah92@gmail.com>
Date: Sun, 23 Aug 2026 23:17:43 +0530
Subject: [PATCH] fix(isISO8601): reject whitespace other than space as
 date-time separator

---
 src/lib/isISO8601.js    |  2 +-
 test/validators.test.js | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/lib/isISO8601.js b/src/lib/isISO8601.js
index 6eea9ae27..873aec756 100644
--- a/src/lib/isISO8601.js
+++ b/src/lib/isISO8601.js
@@ -2,7 +2,7 @@ import assertString from './util/assertString';
 
 /* eslint-disable max-len */
 // from http://goo.gl/0ejHHW
-const iso8601 = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W(0[1-9]|[1-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[0-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/;
+const iso8601 = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W(0[1-9]|[1-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[0-6])))([T ]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/;
 // same as above, except with a strict 'T' separator between date and time
 const iso8601StrictSeparator = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W(0[1-9]|[1-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[0-6])))([T]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/;
 /* eslint-enable max-len */
diff --git a/test/validators.test.js b/test/validators.test.js
index 98d2a12ff..56f623dcb 100644
--- a/test/validators.test.js
+++ b/test/validators.test.js
@@ -12420,6 +12420,22 @@ describe('Validators', () => {
     });
   });
 
+  it('should validate ISO 8601 dates, rejecting whitespace other than a space as the date-time separator', () => {
+    test({
+      validator: 'isISO8601',
+      valid: [
+        '2009-05-19T14:39:22',
+        '2009-05-19 14:39:22',
+      ],
+      invalid: [
+        '2009-05-19\t14:39:22',
+        '2009-05-19\n14:39:22',
+        '2009-05-19\f14:39:22',
+        '2009-05-19\v14:39:22',
+      ],
+    });
+  });
+
   it('should validate ISO 8601 dates, with strict = true (regression)', () => {
     test({
       validator: 'isISO8601',