From 5ef134fce5fb899ff4510e9da41e5d5f2af4b09c Mon Sep 17 00:00:00 2001
From: Thomas Watson <w@tson.dk>
Date: Thu, 19 Feb 2026 11:25:19 +0100
Subject: [PATCH 1/2] stream: fix decoded fromList chunk boundary check

Correct `fromList()` in decoded string mode to compare `n` against the
current chunk length, not the buffer array length.

This prevents over-consuming chunks, which can corrupt readable state
and crash with `TypeError` when mixing `setEncoding()` and `read(n)`.
---
 lib/internal/streams/readable.js                  |  2 +-
 ...test-stream2-read-correct-num-bytes-in-utf8.js | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js

diff --git a/lib/internal/streams/readable.js b/lib/internal/streams/readable.js
index b6145bf2412db1..919c527a2be6f8 100644
--- a/lib/internal/streams/readable.js
+++ b/lib/internal/streams/readable.js
@@ -1669,7 +1669,7 @@ function fromList(n, state) {
         n -= str.length;
         buf[idx++] = null;
       } else {
-        if (n === buf.length) {
+        if (n === str.length) {
           ret += str;
           buf[idx++] = null;
         } else {
diff --git a/test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js b/test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js
new file mode 100644
index 00000000000000..b039c21ec7c43b
--- /dev/null
+++ b/test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js
@@ -0,0 +1,15 @@
+'use strict';
+
+const assert = require('assert');
+const { Readable } = require('stream');
+
+const readable = new Readable({ read() {} });
+readable.setEncoding('utf8');
+
+readable.push('abc');
+readable.push('defgh');
+readable.push(null);
+
+assert.strictEqual(readable.read(5), 'abcde');
+assert.strictEqual(readable.read(3), 'fgh');
+assert.strictEqual(readable.read(1), null);

From 2984f13162380e6f54d0b91a810f7ff359d44ff0 Mon Sep 17 00:00:00 2001
From: Thomas Watson <w@tson.dk>
Date: Thu, 19 Feb 2026 11:43:24 +0100
Subject: [PATCH 2/2] fix lint

---
 test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js b/test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js
index b039c21ec7c43b..476f041e3f4087 100644
--- a/test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js
+++ b/test/parallel/test-stream2-read-correct-num-bytes-in-utf8.js
@@ -1,5 +1,6 @@
 'use strict';
 
+require('../common');
 const assert = require('assert');
 const { Readable } = require('stream');